[gtk+] gears: Update to slightly more modern OpenGL
- From: Emmanuele Bassi <ebassi src gnome org>
- To: commits-list gnome org
- Cc:
- Subject: [gtk+] gears: Update to slightly more modern OpenGL
- Date: Tue, 3 Mar 2015 00:07:57 +0000 (UTC)
commit 0019eb7bf9646f8b364e3cc09aa7351c59d333d7
Author: Emmanuele Bassi <ebassi gnome org>
Date: Tue Mar 3 00:06:35 2015 +0000
gears: Update to slightly more modern OpenGL
Instead of using glxgears, which still uses OpenGL 2.1 and the fixed
pipeline, we use a slightly modified es2gears, OpenGL 3.2, and the
programmable pipeline.
tests/gtkgears.c | 816 ++++++++++++++++++++++++++++++++++++++++--------------
1 files changed, 615 insertions(+), 201 deletions(-)
---
diff --git a/tests/gtkgears.c b/tests/gtkgears.c
index 11e0ac8..dfe66c3 100644
--- a/tests/gtkgears.c
+++ b/tests/gtkgears.c
@@ -1,4 +1,4 @@
-/* The rendering code in here is taken from glxgears, which has the
+/* The rendering code in here is taken from es2gears, which has the
* following copyright notice:
*
* Copyright (C) 1999-2001 Brian Paul All Rights Reserved.
@@ -19,24 +19,93 @@
* BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Ported to GLES2.
+ * Kristian Høgsberg <krh bitplanet net>
+ * May 3, 2010
+ *
+ * Improve GLES2 port:
+ * * Refactor gear drawing.
+ * * Use correct normals for surfaces.
+ * * Improve shader.
+ * * Use perspective projection transformation.
+ * * Add FPS count.
+ * * Add comments.
+ * Alexandros Frantzis <alexandros frantzis linaro org>
+ * Jul 13, 2010
*/
+#define _GNU_SOURCE
#include <math.h>
+#include <stdlib.h>
+#include <string.h>
#include <epoxy/gl.h>
#include "gtkgears.h"
+#define STRIPS_PER_TOOTH 7
+#define VERTICES_PER_TOOTH 34
+#define GEAR_VERTEX_STRIDE 6
+
+/**
+ * Struct describing the vertices in triangle strip
+ */
+struct vertex_strip {
+ /** The first vertex in the strip */
+ GLint first;
+ /** The number of consecutive vertices in the strip after the first */
+ GLint count;
+};
+
+/* Each vertex consist of GEAR_VERTEX_STRIDE GLfloat attributes */
+typedef GLfloat GearVertex[GEAR_VERTEX_STRIDE];
+
+/**
+ * Struct representing a gear.
+ */
+struct gear {
+ /** The array of vertices comprising the gear */
+ GearVertex *vertices;
+ /** The number of vertices comprising the gear */
+ int nvertices;
+ /** The array of triangle strips comprising the gear */
+ struct vertex_strip *strips;
+ /** The number of triangle strips comprising the gear */
+ int nstrips;
+ /** The Vertex Buffer Object holding the vertices in the graphics card */
+ GLuint vbo;
+};
+
typedef struct {
+ /* The view rotation [x, y, z] */
GLfloat view_rot[GTK_GEARS_N_AXIS];
- GLint gear1, gear2, gear3;
+
+ /* The gears */
+ struct gear *gear1;
+ struct gear *gear2;
+ struct gear *gear3;
+
+ /** The location of the shader uniforms */
+ GLuint ModelViewProjectionMatrix_location;
+ GLuint NormalMatrix_location;
+ GLuint LightSourcePosition_location;
+ GLuint MaterialColor_location;
+
+ /* The current gear rotation angle */
GLfloat angle;
+
+ /* The projection matrix */
+ GLfloat ProjectionMatrix[16];
+
+ /* The direction of the directional light for the scene */
+ GLfloat LightSourcePosition[4];
+
gint64 first_frame_time;
guint tick;
GtkLabel *fps_label;
} GtkGearsPrivate;
-
-G_DEFINE_TYPE_WITH_PRIVATE (GtkGears, gtk_gears, GTK_TYPE_GL_AREA);
+G_DEFINE_TYPE_WITH_PRIVATE (GtkGears, gtk_gears, GTK_TYPE_GL_AREA)
static gboolean gtk_gears_render (GtkGLArea *area,
GdkGLContext *context);
@@ -47,16 +116,14 @@ static gboolean gtk_gears_tick (GtkWidget *widget,
GdkFrameClock *frame_clock,
gpointer user_data);
+static void destroy_gear (struct gear *g);
+
GtkWidget *
gtk_gears_new (void)
{
- GtkWidget *gears;
-
- gears = g_object_new (gtk_gears_get_type (),
- "has-depth-buffer", TRUE,
- NULL);
-
- return gears;
+ return g_object_new (gtk_gears_get_type (),
+ "has-depth-buffer", TRUE,
+ NULL);
}
static void
@@ -68,6 +135,11 @@ gtk_gears_init (GtkGears *gears)
priv->view_rot[GTK_GEARS_Y_AXIS] = 30.0;
priv->view_rot[GTK_GEARS_Z_AXIS] = 20.0;
+ priv->LightSourcePosition[0] = 5.0;
+ priv->LightSourcePosition[1] = 5.0;
+ priv->LightSourcePosition[2] = 10.0;
+ priv->LightSourcePosition[3] = 1.0;
+
priv->tick = gtk_widget_add_tick_callback (GTK_WIDGET (gears), gtk_gears_tick, gears, NULL);
}
@@ -81,6 +153,10 @@ gtk_gears_finalize (GObject *obj)
g_clear_object (&priv->fps_label);
+ g_clear_pointer (&priv->gear1, destroy_gear);
+ g_clear_pointer (&priv->gear2, destroy_gear);
+ g_clear_pointer (&priv->gear3, destroy_gear);
+
G_OBJECT_CLASS (gtk_gears_parent_class)->finalize (obj);
}
@@ -94,190 +170,469 @@ gtk_gears_class_init (GtkGearsClass *klass)
}
/*
+ * Fills a gear vertex.
*
- * Draw a gear wheel. You'll probably want to call this function when
- * building a display list since we do a lot of trig here.
+ * @param v the vertex to fill
+ * @param x the x coordinate
+ * @param y the y coordinate
+ * @param z the z coortinate
+ * @param n pointer to the normal table
*
- * Input: inner_radius - radius of hole at center
- * outer_radius - radius at center of teeth
- * width - width of gear
- * teeth - number of teeth
- * tooth_depth - depth of tooth
+ * @return the operation error code
*/
+static GearVertex *
+vert (GearVertex *v,
+ GLfloat x,
+ GLfloat y,
+ GLfloat z,
+ GLfloat n[3])
+{
+ v[0][0] = x;
+ v[0][1] = y;
+ v[0][2] = z;
+ v[0][3] = n[0];
+ v[0][4] = n[1];
+ v[0][5] = n[2];
+
+ return v + 1;
+}
+
static void
-gear(GLfloat inner_radius, GLfloat outer_radius, GLfloat width,
- GLint teeth, GLfloat tooth_depth)
+destroy_gear (struct gear *g)
{
- GLint i;
- GLfloat r0, r1, r2;
- GLfloat angle, da;
- GLfloat u, v, len;
-
- r0 = inner_radius;
- r1 = outer_radius - tooth_depth / 2.0;
- r2 = outer_radius + tooth_depth / 2.0;
-
- da = 2.0 * G_PI / teeth / 4.0;
-
- glShadeModel(GL_FLAT);
-
- glNormal3f(0.0, 0.0, 1.0);
-
- /* draw front face */
- glBegin(GL_QUAD_STRIP);
- for (i = 0; i <= teeth; i++) {
- angle = i * 2.0 * G_PI / teeth;
- glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
- glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
- if (i < teeth) {
- glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
- glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
- width * 0.5);
- }
- }
- glEnd();
-
- /* draw front sides of teeth */
- glBegin(GL_QUADS);
- da = 2.0 * G_PI / teeth / 4.0;
- for (i = 0; i < teeth; i++) {
- angle = i * 2.0 * G_PI / teeth;
-
- glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
- glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
- glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da),
- width * 0.5);
- glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
- width * 0.5);
- }
- glEnd();
-
- glNormal3f(0.0, 0.0, -1.0);
-
- /* draw back face */
- glBegin(GL_QUAD_STRIP);
- for (i = 0; i <= teeth; i++) {
- angle = i * 2.0 * G_PI / teeth;
- glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
- glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
- if (i < teeth) {
- glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
- -width * 0.5);
- glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
- }
- }
- glEnd();
-
- /* draw back sides of teeth */
- glBegin(GL_QUADS);
- da = 2.0 * G_PI / teeth / 4.0;
- for (i = 0; i < teeth; i++) {
- angle = i * 2.0 * G_PI / teeth;
-
- glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
- -width * 0.5);
- glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da),
- -width * 0.5);
- glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
- glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
- }
- glEnd();
-
- /* draw outward faces of teeth */
- glBegin(GL_QUAD_STRIP);
- for (i = 0; i < teeth; i++) {
- angle = i * 2.0 * G_PI / teeth;
-
- glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
- glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
- u = r2 * cos(angle + da) - r1 * cos(angle);
- v = r2 * sin(angle + da) - r1 * sin(angle);
- len = sqrt(u * u + v * v);
- u /= len;
- v /= len;
- glNormal3f(v, -u, 0.0);
- glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
- glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
- glNormal3f(cos(angle), sin(angle), 0.0);
- glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da),
- width * 0.5);
- glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da),
- -width * 0.5);
- u = r1 * cos(angle + 3 * da) - r2 * cos(angle + 2 * da);
- v = r1 * sin(angle + 3 * da) - r2 * sin(angle + 2 * da);
- glNormal3f(v, -u, 0.0);
- glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
- width * 0.5);
- glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
- -width * 0.5);
- glNormal3f(cos(angle), sin(angle), 0.0);
+ g_clear_pointer (&g->strips, g_free);
+ g_free (g);
+}
+
+/**
+ * Create a gear wheel.
+ *
+ * @param inner_radius radius of hole at center
+ * @param outer_radius radius at center of teeth
+ * @param width width of gear
+ * @param teeth number of teeth
+ * @param tooth_depth depth of tooth
+ *
+ * @return pointer to the constructed struct gear
+ */
+static struct gear *
+create_gear (GLfloat inner_radius,
+ GLfloat outer_radius,
+ GLfloat width,
+ GLint teeth,
+ GLfloat tooth_depth)
+{
+ GLfloat r0, r1, r2;
+ GLfloat da;
+ GearVertex *v;
+ struct gear *gear;
+ double s[5], c[5];
+ GLfloat normal[3];
+ int cur_strip = 0;
+ int i;
+
+ /* Allocate memory for the gear */
+ gear = g_malloc (sizeof *gear);
+
+ /* Calculate the radii used in the gear */
+ r0 = inner_radius;
+ r1 = outer_radius - tooth_depth / 2.0;
+ r2 = outer_radius + tooth_depth / 2.0;
+
+ da = 2.0 * M_PI / teeth / 4.0;
+
+ /* Allocate memory for the triangle strip information */
+ gear->nstrips = STRIPS_PER_TOOTH * teeth;
+ gear->strips = g_malloc0_n (gear->nstrips, sizeof (*gear->strips));
+
+ /* Allocate memory for the vertices */
+ gear->vertices = g_malloc0_n (VERTICES_PER_TOOTH * teeth, sizeof(*gear->vertices));
+ v = gear->vertices;
+
+ for (i = 0; i < teeth; i++) {
+ /* A set of macros for making the creation of the gears easier */
+#define GEAR_POINT(p, r, da) do { p.x = (r) * c[(da)]; p.y = (r) * s[(da)]; } while(0)
+#define SET_NORMAL(x, y, z) do { \
+ normal[0] = (x); normal[1] = (y); normal[2] = (z); \
+} while(0)
+
+#define GEAR_VERT(v, point, sign) vert((v), p[(point)].x, p[(point)].y, (sign) * width * 0.5, normal)
+
+#define START_STRIP do { \
+ gear->strips[cur_strip].first = v - gear->vertices; \
+} while(0);
+
+#define END_STRIP do { \
+ int _tmp = (v - gear->vertices); \
+ gear->strips[cur_strip].count = _tmp - gear->strips[cur_strip].first; \
+ cur_strip++; \
+} while (0)
+
+#define QUAD_WITH_NORMAL(p1, p2) do { \
+ SET_NORMAL((p[(p1)].y - p[(p2)].y), -(p[(p1)].x - p[(p2)].x), 0); \
+ v = GEAR_VERT(v, (p1), -1); \
+ v = GEAR_VERT(v, (p1), 1); \
+ v = GEAR_VERT(v, (p2), -1); \
+ v = GEAR_VERT(v, (p2), 1); \
+} while(0)
+ struct point {
+ GLfloat x;
+ GLfloat y;
+ };
+
+ /* Create the 7 points (only x,y coords) used to draw a tooth */
+ struct point p[7];
+
+ /* Calculate needed sin/cos for varius angles */
+ sincos(i * 2.0 * G_PI / teeth + da * 0, &s[0], &c[0]);
+ sincos(i * 2.0 * M_PI / teeth + da * 1, &s[1], &c[1]);
+ sincos(i * 2.0 * M_PI / teeth + da * 2, &s[2], &c[2]);
+ sincos(i * 2.0 * M_PI / teeth + da * 3, &s[3], &c[3]);
+ sincos(i * 2.0 * M_PI / teeth + da * 4, &s[4], &c[4]);
+
+ GEAR_POINT(p[0], r2, 1);
+ GEAR_POINT(p[1], r2, 2);
+ GEAR_POINT(p[2], r1, 0);
+ GEAR_POINT(p[3], r1, 3);
+ GEAR_POINT(p[4], r0, 0);
+ GEAR_POINT(p[5], r1, 4);
+ GEAR_POINT(p[6], r0, 4);
+
+ /* Front face */
+ START_STRIP;
+ SET_NORMAL(0, 0, 1.0);
+ v = GEAR_VERT(v, 0, +1);
+ v = GEAR_VERT(v, 1, +1);
+ v = GEAR_VERT(v, 2, +1);
+ v = GEAR_VERT(v, 3, +1);
+ v = GEAR_VERT(v, 4, +1);
+ v = GEAR_VERT(v, 5, +1);
+ v = GEAR_VERT(v, 6, +1);
+ END_STRIP;
+
+ /* Inner face */
+ START_STRIP;
+ QUAD_WITH_NORMAL(4, 6);
+ END_STRIP;
+
+ /* Back face */
+ START_STRIP;
+ SET_NORMAL(0, 0, -1.0);
+ v = GEAR_VERT(v, 6, -1);
+ v = GEAR_VERT(v, 5, -1);
+ v = GEAR_VERT(v, 4, -1);
+ v = GEAR_VERT(v, 3, -1);
+ v = GEAR_VERT(v, 2, -1);
+ v = GEAR_VERT(v, 1, -1);
+ v = GEAR_VERT(v, 0, -1);
+ END_STRIP;
+
+ /* Outer face */
+ START_STRIP;
+ QUAD_WITH_NORMAL(0, 2);
+ END_STRIP;
+
+ START_STRIP;
+ QUAD_WITH_NORMAL(1, 0);
+ END_STRIP;
+
+ START_STRIP;
+ QUAD_WITH_NORMAL(3, 1);
+ END_STRIP;
+
+ START_STRIP;
+ QUAD_WITH_NORMAL(5, 3);
+ END_STRIP;
+ }
+
+ gear->nvertices = (v - gear->vertices);
+
+ /* Store the vertices in a vertex buffer object (VBO) */
+ glGenBuffers (1, &gear->vbo);
+ glBindBuffer (GL_ARRAY_BUFFER, gear->vbo);
+ glBufferData (GL_ARRAY_BUFFER,
+ gear->nvertices * sizeof(GearVertex),
+ gear->vertices,
+ GL_STATIC_DRAW);
+
+ return gear;
+}
+
+/**
+ * Multiplies two 4x4 matrices.
+ *
+ * The result is stored in matrix m.
+ *
+ * @param m the first matrix to multiply
+ * @param n the second matrix to multiply
+ */
+static void
+multiply (GLfloat *m, const GLfloat *n)
+{
+ GLfloat tmp[16];
+ const GLfloat *row, *column;
+ div_t d;
+ int i, j;
+
+ for (i = 0; i < 16; i++) {
+ tmp[i] = 0;
+ d = div(i, 4);
+ row = n + d.quot * 4;
+ column = m + d.rem;
+ for (j = 0; j < 4; j++)
+ tmp[i] += row[j] * column[j * 4];
}
+ memcpy(m, &tmp, sizeof tmp);
+}
- glVertex3f(r1 * cos(0), r1 * sin(0), width * 0.5);
- glVertex3f(r1 * cos(0), r1 * sin(0), -width * 0.5);
+/**
+ * Rotates a 4x4 matrix.
+ *
+ * @param[in,out] m the matrix to rotate
+ * @param angle the angle to rotate
+ * @param x the x component of the direction to rotate to
+ * @param y the y component of the direction to rotate to
+ * @param z the z component of the direction to rotate to
+ */
+static void
+rotate(GLfloat *m, GLfloat angle, GLfloat x, GLfloat y, GLfloat z)
+{
+ double s, c;
- glEnd();
+ sincos(angle, &s, &c);
+ GLfloat r[16] = {
+ x * x * (1 - c) + c, y * x * (1 - c) + z * s, x * z * (1 - c) - y * s, 0,
+ x * y * (1 - c) - z * s, y * y * (1 - c) + c, y * z * (1 - c) + x * s, 0,
+ x * z * (1 - c) + y * s, y * z * (1 - c) - x * s, z * z * (1 - c) + c, 0,
+ 0, 0, 0, 1
+ };
- glShadeModel(GL_SMOOTH);
+ multiply(m, r);
+}
- /* draw inside radius cylinder */
- glBegin(GL_QUAD_STRIP);
- for (i = 0; i <= teeth; i++) {
- angle = i * 2.0 * G_PI / teeth;
- glNormal3f(-cos(angle), -sin(angle), 0.0);
- glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
- glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
- }
- glEnd();
+/**
+ * Translates a 4x4 matrix.
+ *
+ * @param[in,out] m the matrix to translate
+ * @param x the x component of the direction to translate to
+ * @param y the y component of the direction to translate to
+ * @param z the z component of the direction to translate to
+ */
+static void
+translate(GLfloat *m, GLfloat x, GLfloat y, GLfloat z)
+{
+ GLfloat t[16] = { 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, x, y, z, 1 };
+
+ multiply(m, t);
+}
+
+/**
+ * Creates an identity 4x4 matrix.
+ *
+ * @param m the matrix make an identity matrix
+ */
+static void
+identity(GLfloat *m)
+{
+ GLfloat t[16] = {
+ 1.0, 0.0, 0.0, 0.0,
+ 0.0, 1.0, 0.0, 0.0,
+ 0.0, 0.0, 1.0, 0.0,
+ 0.0, 0.0, 0.0, 1.0,
+ };
+
+ memcpy(m, t, sizeof(t));
+}
+
+/**
+ * Transposes a 4x4 matrix.
+ *
+ * @param m the matrix to transpose
+ */
+static void
+transpose(GLfloat *m)
+{
+ GLfloat t[16] = {
+ m[0], m[4], m[8], m[12],
+ m[1], m[5], m[9], m[13],
+ m[2], m[6], m[10], m[14],
+ m[3], m[7], m[11], m[15]};
+
+ memcpy(m, t, sizeof(t));
+}
+
+/**
+ * Inverts a 4x4 matrix.
+ *
+ * This function can currently handle only pure translation-rotation matrices.
+ * Read http://www.gamedev.net/community/forums/topic.asp?topic_id=425118
+ * for an explanation.
+ */
+static void
+invert(GLfloat *m)
+{
+ GLfloat t[16];
+ identity(t);
+
+ // Extract and invert the translation part 't'. The inverse of a
+ // translation matrix can be calculated by negating the translation
+ // coordinates.
+ t[12] = -m[12]; t[13] = -m[13]; t[14] = -m[14];
+
+ // Invert the rotation part 'r'. The inverse of a rotation matrix is
+ // equal to its transpose.
+ m[12] = m[13] = m[14] = 0;
+ transpose(m);
+
+ // inv(m) = inv(r) * inv(t)
+ multiply(m, t);
+}
+
+/**
+ * Calculate a perspective projection transformation.
+ *
+ * @param m the matrix to save the transformation in
+ * @param fovy the field of view in the y direction
+ * @param aspect the view aspect ratio
+ * @param zNear the near clipping plane
+ * @param zFar the far clipping plane
+ */
+void perspective(GLfloat *m, GLfloat fovy, GLfloat aspect, GLfloat zNear, GLfloat zFar)
+{
+ GLfloat tmp[16];
+ identity(tmp);
+
+ double sine, cosine, cotangent, deltaZ;
+ GLfloat radians = fovy / 2 * M_PI / 180;
+
+ deltaZ = zFar - zNear;
+ sincos(radians, &sine, &cosine);
+
+ if ((deltaZ == 0) || (sine == 0) || (aspect == 0))
+ return;
+
+ cotangent = cosine / sine;
+
+ tmp[0] = cotangent / aspect;
+ tmp[5] = cotangent;
+ tmp[10] = -(zFar + zNear) / deltaZ;
+ tmp[11] = -1;
+ tmp[14] = -2 * zNear * zFar / deltaZ;
+ tmp[15] = 0;
+
+ memcpy(m, tmp, sizeof(tmp));
+}
+
+/**
+ * Draws a gear.
+ *
+ * @param gear the gear to draw
+ * @param transform the current transformation matrix
+ * @param x the x position to draw the gear at
+ * @param y the y position to draw the gear at
+ * @param angle the rotation angle of the gear
+ * @param color the color of the gear
+ */
+static void
+draw_gear(GtkGears *self,
+ struct gear *gear,
+ GLfloat *transform,
+ GLfloat x,
+ GLfloat y,
+ GLfloat angle,
+ const GLfloat color[4])
+{
+ GtkGearsPrivate *priv = gtk_gears_get_instance_private (self);
+ GLfloat model_view[16];
+ GLfloat normal_matrix[16];
+ GLfloat model_view_projection[16];
+ int n;
+
+ /* Translate and rotate the gear */
+ memcpy(model_view, transform, sizeof (model_view));
+ translate(model_view, x, y, 0);
+ rotate(model_view, 2 * G_PI * angle / 360.0, 0, 0, 1);
+
+ /* Create and set the ModelViewProjectionMatrix */
+ memcpy(model_view_projection, priv->ProjectionMatrix, sizeof(model_view_projection));
+ multiply(model_view_projection, model_view);
+
+ glUniformMatrix4fv(priv->ModelViewProjectionMatrix_location, 1, GL_FALSE,
+ model_view_projection);
+
+ /*
+ * Create and set the NormalMatrix. It's the inverse transpose of the
+ * ModelView matrix.
+ */
+ memcpy(normal_matrix, model_view, sizeof (normal_matrix));
+ invert(normal_matrix);
+ transpose(normal_matrix);
+ glUniformMatrix4fv(priv->NormalMatrix_location, 1, GL_FALSE, normal_matrix);
+
+ /* Set the gear color */
+ glUniform4fv(priv->MaterialColor_location, 1, color);
+
+ /* Set the vertex buffer object to use */
+ glBindBuffer(GL_ARRAY_BUFFER, gear->vbo);
+
+ /* Set up the position of the attributes in the vertex buffer object */
+ glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), NULL);
+ glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), (GLfloat *) 0 + 3);
+
+ /* Enable the attributes */
+ glEnableVertexAttribArray(0);
+ glEnableVertexAttribArray(1);
+
+ /* Draw the triangle strips that comprise the gear */
+ for (n = 0; n < gear->nstrips; n++) {
+ glDrawArrays(GL_TRIANGLE_STRIP, gear->strips[n].first, gear->strips[n].count);
+ }
+
+ /* Disable the attributes */
+ glDisableVertexAttribArray(1);
+ glDisableVertexAttribArray(0);
}
/* new window size or exposure */
static void
-reshape(int width, int height)
+reshape(GtkGears *gears, int width, int height)
{
- GLfloat h = (GLfloat) height / (GLfloat) width;
+ GtkGearsPrivate *priv = gtk_gears_get_instance_private (gears);
- glMatrixMode(GL_PROJECTION);
- glLoadIdentity();
- glFrustum(-1.0, 1.0, -h, h, 5.0, 60.0);
+ /* Update the projection matrix */
+ perspective (priv->ProjectionMatrix, 60.0, width / (float)height, 1.0, 1024.0);
- glMatrixMode(GL_MODELVIEW);
- glLoadIdentity();
- glTranslatef(0.0, 0.0, -40.0);
+ /* Set the viewport */
+ glViewport (0, 0, (GLint) width, (GLint) height);
}
static gboolean
gtk_gears_render (GtkGLArea *area,
GdkGLContext *context)
{
- GtkGearsPrivate *priv = gtk_gears_get_instance_private (GTK_GEARS (area));
-
- glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+ static const GLfloat red[4] = { 0.8, 0.1, 0.0, 1.0 };
+ static const GLfloat green[4] = { 0.0, 0.8, 0.2, 1.0 };
+ static const GLfloat blue[4] = { 0.2, 0.2, 1.0, 1.0 };
- glPushMatrix();
- glRotatef(priv->view_rot[GTK_GEARS_X_AXIS], 1.0, 0.0, 0.0);
- glRotatef(priv->view_rot[GTK_GEARS_Y_AXIS], 0.0, 1.0, 0.0);
- glRotatef(priv->view_rot[GTK_GEARS_Z_AXIS], 0.0, 0.0, 1.0);
+ GtkGears *self = GTK_GEARS (area);
+ GtkGearsPrivate *priv = gtk_gears_get_instance_private (self);
+ GLfloat transform[16];
- glPushMatrix();
- glTranslatef(-3.0, -2.0, 0.0);
- glRotatef(priv->angle, 0.0, 0.0, 1.0);
- glCallList(priv->gear1);
- glPopMatrix();
+ identity (transform);
- glPushMatrix();
- glTranslatef(3.1, -2.0, 0.0);
- glRotatef(-2.0 * priv->angle - 9.0, 0.0, 0.0, 1.0);
- glCallList(priv->gear2);
- glPopMatrix();
+ glClearColor (0.0, 0.0, 0.0, 0.0);
+ glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
- glPushMatrix();
- glTranslatef(-3.1, 4.2, 0.0);
- glRotatef(-2.0 * priv->angle - 25.0, 0.0, 0.0, 1.0);
- glCallList(priv->gear3);
- glPopMatrix();
+ /* Translate and rotate the view */
+ translate (transform, 0, 0, -20);
+ rotate (transform, 2 * G_PI * priv->view_rot[0] / 360.0, 1, 0, 0);
+ rotate (transform, 2 * G_PI * priv->view_rot[1] / 360.0, 0, 1, 0);
+ rotate (transform, 2 * G_PI * priv->view_rot[2] / 360.0, 0, 0, 1);
- glPopMatrix();
+ /* Draw the gears */
+ draw_gear (self, priv->gear1, transform, -3.0, -2.0, priv->angle, red);
+ draw_gear (self, priv->gear2, transform, 3.1, -2.0, -2 * priv->angle - 9.0, green);
+ draw_gear (self, priv->gear3, transform, -3.1, 4.2, -2 * priv->angle - 25.0, blue);
return TRUE;
}
@@ -293,55 +648,114 @@ gtk_gears_size_allocate (GtkWidget *widget,
if (gtk_widget_get_realized (widget))
{
gtk_gl_area_make_current (glarea);
- reshape (allocation->width, allocation->height);
+ reshape ((GtkGears *) glarea, allocation->width, allocation->height);
}
}
+static const char vertex_shader[] =
+"#version 150\n"
+"\n"
+"in vec3 position;\n"
+"in vec3 normal;\n"
+"\n"
+"uniform mat4 ModelViewProjectionMatrix;\n"
+"uniform mat4 NormalMatrix;\n"
+"uniform vec4 LightSourcePosition;\n"
+"uniform vec4 MaterialColor;\n"
+"\n"
+"smooth out vec4 Color;\n"
+"\n"
+"void main(void)\n"
+"{\n"
+" // Transform the normal to eye coordinates\n"
+" vec3 N = normalize(vec3(NormalMatrix * vec4(normal, 1.0)));\n"
+"\n"
+" // The LightSourcePosition is actually its direction for directional light\n"
+" vec3 L = normalize(LightSourcePosition.xyz);\n"
+"\n"
+" // Multiply the diffuse value by the vertex color (which is fixed in this case)\n"
+" // to get the actual color that we will use to draw this vertex with\n"
+" float diffuse = max(dot(N, L), 0.0);\n"
+" Color = diffuse * MaterialColor;\n"
+"\n"
+" // Transform the position to clip coordinates\n"
+" gl_Position = ModelViewProjectionMatrix * vec4(position, 1.0);\n"
+"}";
+
+static const char fragment_shader[] =
+"#version 150\n"
+"\n"
+"smooth in vec4 Color;\n"
+"\n"
+"void main(void)\n"
+"{\n"
+" gl_FragColor = Color;\n"
+"}";
+
static void
gtk_gears_realize (GtkWidget *widget)
{
GtkGLArea *glarea = GTK_GL_AREA (widget);
- GtkGears *gears = GTK_GEARS(widget);
+ GtkGears *gears = GTK_GEARS (widget);
GtkGearsPrivate *priv = gtk_gears_get_instance_private (gears);
- GtkAllocation allocation;
- static GLfloat pos[4] = { 5.0, 5.0, 10.0, 0.0 };
- static GLfloat red[4] = { 0.8, 0.1, 0.0, 1.0 };
- static GLfloat green[4] = { 0.0, 0.8, 0.2, 1.0 };
- static GLfloat blue[4] = { 0.2, 0.2, 1.0, 1.0 };
+ GLuint vao, v, f, program;
+ const char *p;
+ char msg[512];
GTK_WIDGET_CLASS (gtk_gears_parent_class)->realize (widget);
gtk_gl_area_make_current (glarea);
- glLightfv(GL_LIGHT0, GL_POSITION, pos);
- glEnable(GL_CULL_FACE);
- glEnable(GL_LIGHTING);
- glEnable(GL_LIGHT0);
- glEnable(GL_DEPTH_TEST);
+ glEnable (GL_CULL_FACE);
+ glEnable (GL_DEPTH_TEST);
+
+ /* Create the VAO */
+ glGenVertexArrays (1, &vao);
+ glBindVertexArray (vao);
+
+ /* Compile the vertex shader */
+ p = vertex_shader;
+ v = glCreateShader(GL_VERTEX_SHADER);
+ glShaderSource(v, 1, &p, NULL);
+ glCompileShader(v);
+ glGetShaderInfoLog(v, sizeof msg, NULL, msg);
+ g_print ("vertex shader info: %s\n", msg);
+
+ /* Compile the fragment shader */
+ p = fragment_shader;
+ f = glCreateShader(GL_FRAGMENT_SHADER);
+ glShaderSource(f, 1, &p, NULL);
+ glCompileShader(f);
+ glGetShaderInfoLog(f, sizeof msg, NULL, msg);
+ g_print ("fragment shader info: %s\n", msg);
+
+ /* Create and link the shader program */
+ program = glCreateProgram();
+ glAttachShader(program, v);
+ glAttachShader(program, f);
+ glBindAttribLocation(program, 0, "position");
+ glBindAttribLocation(program, 1, "normal");
+
+ glLinkProgram(program);
+ glGetProgramInfoLog(program, sizeof msg, NULL, msg);
+ g_print ("program info: %s\n", msg);
+
+ /* Enable the shaders */
+ glUseProgram(program);
+
+ /* Get the locations of the uniforms so we can access them */
+ priv->ModelViewProjectionMatrix_location = glGetUniformLocation(program, "ModelViewProjectionMatrix");
+ priv->NormalMatrix_location = glGetUniformLocation(program, "NormalMatrix");
+ priv->LightSourcePosition_location = glGetUniformLocation(program, "LightSourcePosition");
+ priv->MaterialColor_location = glGetUniformLocation(program, "MaterialColor");
+
+ /* Set the LightSourcePosition uniform which is constant throught the program */
+ glUniform4fv(priv->LightSourcePosition_location, 1, priv->LightSourcePosition);
/* make the gears */
- priv->gear1 = glGenLists(1);
- glNewList(priv->gear1, GL_COMPILE);
- glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, red);
- gear(1.0, 4.0, 1.0, 20, 0.7);
- glEndList();
-
- priv->gear2 = glGenLists(1);
- glNewList(priv->gear2, GL_COMPILE);
- glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, green);
- gear(0.5, 2.0, 2.0, 10, 0.7);
- glEndList();
-
- priv->gear3 = glGenLists(1);
- glNewList(priv->gear3, GL_COMPILE);
- glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, blue);
- gear(1.3, 2.0, 0.5, 10, 0.7);
- glEndList();
-
- glEnable(GL_NORMALIZE);
-
- gtk_widget_get_allocation (widget, &allocation);
- reshape (allocation.width, allocation.height);
+ priv->gear1 = create_gear(1.0, 4.0, 1.0, 20, 0.7);
+ priv->gear2 = create_gear(0.5, 2.0, 2.0, 10, 0.7);
+ priv->gear3 = create_gear(1.3, 2.0, 0.5, 10, 0.7);
}
static gboolean
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