[retro-gtk] Add RetroGLSLFilter

[Adrien Plazas <aplazas src gnome org>]

commit 7ba901b9d33a9a25f90dee754fef773e6b552675
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Sun Oct 15 09:36:05 2017 +0200

    Add RetroGLSLFilter
    
    This will be used in the next commit to handle GLSL video filters.

 retro-gtk/retro-glsl-filter.c |  333 +++++++++++++++++++++++++++++++++++++++++
 retro-gtk/retro-glsl-filter.h |   39 +++++
 2 files changed, 372 insertions(+), 0 deletions(-)
---
diff --git a/retro-gtk/retro-glsl-filter.c b/retro-gtk/retro-glsl-filter.c
new file mode 100644
index 0000000..1620b8c
--- /dev/null
+++ b/retro-gtk/retro-glsl-filter.c
@@ -0,0 +1,333 @@
+// This file is part of retro-gtk. License: GPL-3.0+.
+
+#include "retro-glsl-filter.h"
+
+struct _RetroGLSLFilter
+{
+  GObject parent_instance;
+  GBytes *vertex;
+  GBytes *fragment;
+  GLenum wrap;
+  GLenum filter;
+  GLuint vertex_shader;
+  GLuint fragment_shader;
+  GLuint program;
+};
+
+G_DEFINE_TYPE (RetroGLSLFilter, retro_glsl_filter, G_TYPE_OBJECT)
+
+#define GLSL_FILTER_GROUP "GLSL Filter"
+
+static const gchar *
+g_key_file_try_get_string (GKeyFile    *key_file,
+                           const gchar *group,
+                           const gchar *key)
+{
+  const gchar *value;
+  GError *inner_error = NULL;
+
+  value = g_key_file_get_string (key_file, group, key, &inner_error);
+  if (G_UNLIKELY (inner_error != NULL)) {
+    g_debug ("%s", inner_error->message);
+    g_clear_error (&inner_error);
+
+    return NULL;
+  }
+
+  return value;
+}
+
+static GBytes *
+g_file_try_read_bytes (GFile *file)
+{
+  GFileInputStream *stream;
+  goffset size;
+  GBytes *bytes;
+  GError *inner_error = NULL;
+
+  stream = g_file_read (file, NULL, &inner_error);
+  if (G_UNLIKELY (inner_error != NULL)) {
+    g_debug ("%s", inner_error->message);
+    g_clear_error (&inner_error);
+
+    return NULL;
+  }
+
+  g_seekable_seek (G_SEEKABLE (stream), 0, G_SEEK_END, NULL, &inner_error);
+  if (G_UNLIKELY (inner_error != NULL)) {
+    g_debug ("%s", inner_error->message);
+    g_clear_error (&inner_error);
+    g_object_unref (stream);
+
+    return NULL;
+  }
+
+  size = g_seekable_tell (G_SEEKABLE (stream));
+
+  g_seekable_seek (G_SEEKABLE (stream), 0, G_SEEK_SET, NULL, &inner_error);
+  if (G_UNLIKELY (inner_error != NULL)) {
+    g_debug ("%s", inner_error->message);
+    g_clear_error (&inner_error);
+    g_object_unref (stream);
+
+    return NULL;
+  }
+
+  bytes = g_input_stream_read_bytes (G_INPUT_STREAM (stream), size, NULL, &inner_error);
+  if (G_UNLIKELY (inner_error != NULL)) {
+    g_debug ("%s", inner_error->message);
+    g_clear_error (&inner_error);
+    g_object_unref (stream);
+
+    return NULL;
+  }
+
+  g_object_unref (stream);
+
+  return bytes;
+}
+
+static GBytes *
+g_file_try_read_child_bytes (GFile       *parent,
+                             const gchar *child_filename)
+{
+  GFile *file;
+  GBytes *bytes;
+
+  file = g_file_get_child (parent, child_filename);
+  bytes = g_file_try_read_bytes (file);
+  g_object_unref (file);
+
+  return bytes;
+}
+
+static GBytes *
+g_key_file_try_read_child_bytes (GKeyFile    *key_file,
+                                 const gchar *group,
+                                 const gchar *key,
+                                 GFile       *parent)
+{
+  const gchar *value;
+
+  value = g_key_file_try_get_string (key_file, group, key);
+  if (value == NULL)
+    return NULL;
+
+  return g_file_try_read_child_bytes (parent, value);
+}
+
+RetroGLSLFilter *
+retro_glsl_filter_new (const char  *uri,
+                       GError     **error)
+{
+  RetroGLSLFilter *self;
+  GKeyFile *key_file;
+  GFile *file;
+  GFile *parent;
+  GFileInputStream *stream;
+  GBytes *bytes;
+  const gchar *value;
+  GError *inner_error = NULL;
+
+  g_return_val_if_fail (uri != NULL, NULL);
+
+  file = g_file_new_for_uri (uri);
+  stream = g_file_read (file, NULL, &inner_error);
+  if (G_UNLIKELY (inner_error != NULL)) {
+    g_propagate_error (error, inner_error);
+    g_object_unref (file);
+
+    return NULL;
+  }
+
+  bytes = g_input_stream_read_bytes (G_INPUT_STREAM (stream), 4096, NULL, error);
+  if (G_UNLIKELY (inner_error != NULL)) {
+    g_propagate_error (error, inner_error);
+    g_object_unref (file);
+    g_object_unref (stream);
+
+    return NULL;
+  }
+
+  g_object_unref (stream);
+
+  key_file = g_key_file_new ();
+  g_key_file_load_from_bytes (key_file, bytes, G_KEY_FILE_NONE, &inner_error);
+  if (G_UNLIKELY (inner_error != NULL)) {
+    g_propagate_error (error, inner_error);
+    g_object_unref (file);
+    g_bytes_unref (bytes);
+    g_key_file_unref (key_file);
+
+    return NULL;
+  }
+
+  g_bytes_unref (bytes);
+
+  self = g_object_new (RETRO_TYPE_GLSL_FILTER, NULL);
+
+  value = g_key_file_try_get_string (key_file, GLSL_FILTER_GROUP, "Filter");
+  if (g_strcmp0 (value, "Linear") == 0)
+    self->filter = GL_LINEAR;
+  else if (g_strcmp0 (value, "Nearest") == 0)
+    self->filter = GL_NEAREST;
+  else
+    self->filter = GL_LINEAR;
+
+  value = g_key_file_try_get_string (key_file, GLSL_FILTER_GROUP, "Wrap");
+  if (g_strcmp0 (value, "Border") == 0)
+    self->wrap = GL_CLAMP_TO_BORDER;
+  else if (g_strcmp0 (value, "Edge") == 0)
+    self->wrap = GL_CLAMP_TO_EDGE;
+  else
+    self->wrap = GL_CLAMP_TO_BORDER;
+
+  parent = g_file_get_parent (file);
+  g_object_unref (file);
+
+  self->vertex = g_key_file_try_read_child_bytes (key_file,
+                                                  GLSL_FILTER_GROUP,
+                                                  "Vertex",
+                                                  parent);
+
+  if (self->vertex == NULL)
+    self->vertex = g_file_try_read_child_bytes (parent, "sharp.vs");
+
+  self->fragment = g_key_file_try_read_child_bytes (key_file,
+                                                    GLSL_FILTER_GROUP,
+                                                    "Fragment",
+                                                    parent);
+
+  if (self->fragment == NULL)
+    self->fragment = g_file_try_read_child_bytes (parent, "sharp.fs");
+
+  g_object_unref (parent);
+  g_key_file_unref (key_file);
+
+  return self;
+}
+
+static void
+retro_glsl_filter_finalize (GObject *object)
+{
+  RetroGLSLFilter *self = (RetroGLSLFilter *) object;
+
+  if (self->vertex != NULL)
+    g_bytes_unref (self->vertex);
+  if (self->fragment != NULL)
+    g_bytes_unref (self->fragment);
+  glDeleteShader (self->vertex_shader);
+  glDeleteShader (self->fragment_shader);
+  glDeleteProgram (self->program);
+
+  G_OBJECT_CLASS (retro_glsl_filter_parent_class)->finalize (object);
+}
+
+static void
+retro_glsl_filter_class_init (RetroGLSLFilterClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->finalize = retro_glsl_filter_finalize;
+}
+
+static void
+retro_glsl_filter_init (RetroGLSLFilter *self)
+{
+}
+
+void
+retro_glsl_filter_apply_texture_params (RetroGLSLFilter *self)
+{
+  g_return_if_fail (RETRO_IS_GLSL_FILTER (self));
+
+  glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, self->wrap);
+  glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, self->wrap);
+  glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, self->filter);
+  glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, self->filter);
+}
+
+static GLuint
+create_shader (GBytes *source_bytes,
+               GLenum  shader_type)
+{
+  const gchar *source;
+  GLuint shader;
+
+  source = g_bytes_get_data (source_bytes, NULL);
+  shader = glCreateShader (shader_type);
+  glShaderSource (shader, 1, &source, NULL);
+  glCompileShader (shader);
+
+  return shader;
+}
+
+void
+retro_glsl_filter_prepare_program (RetroGLSLFilter *self)
+{
+  g_return_if_fail (RETRO_IS_GLSL_FILTER (self));
+
+  self->vertex_shader = create_shader (self->vertex, GL_VERTEX_SHADER);
+  self->fragment_shader = create_shader (self->fragment, GL_FRAGMENT_SHADER);
+
+  self->program = glCreateProgram();
+  glAttachShader (self->program, self->vertex_shader);
+  glAttachShader (self->program, self->fragment_shader);
+  glLinkProgram (self->program);
+}
+
+void
+retro_glsl_filter_use_program (RetroGLSLFilter *self)
+{
+  g_return_if_fail (RETRO_IS_GLSL_FILTER (self));
+
+  glUseProgram (self->program);
+}
+
+void
+retro_glsl_filter_set_attribute_pointer (RetroGLSLFilter *self,
+                                         const gchar     *name,
+                                         GLint            size,
+                                         GLenum           type,
+                                         GLboolean        normalized,
+                                         GLsizei          stride,
+                                         const GLvoid    *pointer)
+{
+  GLint location;
+
+  g_return_if_fail (RETRO_IS_GLSL_FILTER (self));
+
+  location = glGetAttribLocation (self->program, name);
+  glVertexAttribPointer (location, size, type, normalized, stride, pointer);
+  glEnableVertexAttribArray (location);
+}
+
+
+void
+retro_glsl_filter_set_uniform_1f (RetroGLSLFilter *self,
+                                  const gchar     *name,
+                                  gfloat           v0)
+{
+  GLint location;
+
+  g_return_if_fail (RETRO_IS_GLSL_FILTER (self));
+
+  location = glGetUniformLocation (self->program, name);
+  glUniform1f (location, v0);
+}
+
+void
+retro_glsl_filter_set_uniform_4f (RetroGLSLFilter *self,
+                                  const gchar     *name,
+                                  gfloat           v0,
+                                  gfloat           v1,
+                                  gfloat           v2,
+                                  gfloat           v3)
+{
+  GLint location;
+
+  g_return_if_fail (RETRO_IS_GLSL_FILTER (self));
+
+  location = glGetUniformLocation (self->program, name);
+  glUniform4f (location, v0, v1, v2, v3);
+}
diff --git a/retro-gtk/retro-glsl-filter.h b/retro-gtk/retro-glsl-filter.h
new file mode 100644
index 0000000..a9d0e11
--- /dev/null
+++ b/retro-gtk/retro-glsl-filter.h
@@ -0,0 +1,39 @@
+#ifndef RETRO_GLSL_FILTER_H
+#define RETRO_GLSL_FILTER_H
+
+#include <epoxy/gl.h>
+#include <gio/gio.h>
+#include <glib-object.h>
+
+G_BEGIN_DECLS
+
+#define RETRO_TYPE_GLSL_FILTER (retro_glsl_filter_get_type())
+
+G_DECLARE_FINAL_TYPE (RetroGLSLFilter, retro_glsl_filter, RETRO, GLSL_FILTER, GObject)
+
+RetroGLSLFilter *retro_glsl_filter_new (const char  *uri,
+                                        GError     **error);
+void retro_glsl_filter_apply_texture_params (RetroGLSLFilter *self);
+void retro_glsl_filter_prepare_program (RetroGLSLFilter *self);
+void retro_glsl_filter_use_program (RetroGLSLFilter *self);
+void retro_glsl_filter_set_attribute_pointer (RetroGLSLFilter *self,
+                                              const gchar     *name,
+                                              GLint            size,
+                                              GLenum           type,
+                                              GLboolean        normalized,
+                                              GLsizei          stride,
+                                              const GLvoid    *pointer);
+void retro_glsl_filter_set_uniform_1f (RetroGLSLFilter *self,
+                                       const gchar     *name,
+                                       gfloat           v0);
+void retro_glsl_filter_set_uniform_4f (RetroGLSLFilter *self,
+                                       const gchar     *name,
+                                       gfloat           v0,
+                                       gfloat           v1,
+                                       gfloat           v2,
+                                       gfloat           v3);
+
+G_END_DECLS
+
+#endif /* RETRO_GLSL_FILTER_H */
+