[gtk+] gl renderer: Fix shaders for gles

[Timm Bäder <baedert src gnome org>]

commit bbf6e81c1f55d534ef20a2994a722fe4e0766d2f
Author: Timm Bäder <mail baedert org>
Date:   Mon Jan 8 18:59:01 2018 +0100

    gl renderer: Fix shaders for gles
    
    Remove uniform initializers, add casts to float, etc.

 gsk/resources/glsl/blur.fs.glsl          |    8 +-
 gsk/resources/glsl/border.fs.glsl        |    2 +-
 gsk/resources/glsl/cross_fade.fs.glsl    |    2 +-
 gsk/resources/glsl/es2_common.fs.glsl    |   98 ++++++++++++++++++++++++++++--
 gsk/resources/glsl/es2_common.vs.glsl    |    5 +-
 gsk/resources/glsl/outset_shadow.fs.glsl |    6 +-
 6 files changed, 106 insertions(+), 15 deletions(-)
---
diff --git a/gsk/resources/glsl/blur.fs.glsl b/gsk/resources/glsl/blur.fs.glsl
index 78107aa..19be916 100644
--- a/gsk/resources/glsl/blur.fs.glsl
+++ b/gsk/resources/glsl/blur.fs.glsl
@@ -1,5 +1,5 @@
-uniform float u_blur_radius = 40.0;
-uniform vec2 u_blur_size = vec2(393, 393);
+uniform float u_blur_radius;// = 40.0;
+uniform vec2 u_blur_size;// = vec2(393, 393);
 
 float Gaussian (float sigma, float x) {
   return exp ( - (x * x) / (2.0 * sigma * sigma));
@@ -18,11 +18,11 @@ vec4 blur_pixel (in vec2 uv) {
 
   for (int y = -half_radius; y < half_radius; y ++) {
     float fy = Gaussian (radius / 2.0, float(y));
-    float offset_y = y * pixel_size_y;
+    float offset_y = float(y) * pixel_size_y;
 
     for (int x = -half_radius; x < half_radius; x ++) {
       float fx = Gaussian (radius / 2.0, float(x));
-      float offset_x = x * pixel_size_x;
+      float offset_x = float(x) * pixel_size_x;
 
       vec4 c = Texture(u_source, uv + vec2(offset_x, offset_y));
       total += fx * fy;
diff --git a/gsk/resources/glsl/border.fs.glsl b/gsk/resources/glsl/border.fs.glsl
index 409c362..59b1b81 100644
--- a/gsk/resources/glsl/border.fs.glsl
+++ b/gsk/resources/glsl/border.fs.glsl
@@ -1,4 +1,4 @@
-uniform vec4 u_color = vec4(1, 0, 1, 1);
+uniform vec4 u_color;// = vec4(1, 0, 1, 1);
 uniform vec4 u_widths;
 
 // For border we abuse, ehm, re-use, the global clip
diff --git a/gsk/resources/glsl/cross_fade.fs.glsl b/gsk/resources/glsl/cross_fade.fs.glsl
index a38b504..8f0f411 100644
--- a/gsk/resources/glsl/cross_fade.fs.glsl
+++ b/gsk/resources/glsl/cross_fade.fs.glsl
@@ -7,6 +7,6 @@ void main() {
   vec4 source2 = Texture(u_source2, vUv); // end child
 
   float p = u_progress;
-  vec4 color = ((1 - p) * source1) + (p * source2);
+  vec4 color = ((1.0 - p) * source1) + (p * source2);
   setOutputColor(color);
 }
diff --git a/gsk/resources/glsl/es2_common.fs.glsl b/gsk/resources/glsl/es2_common.fs.glsl
index 4cbe577..0ed8df8 100644
--- a/gsk/resources/glsl/es2_common.fs.glsl
+++ b/gsk/resources/glsl/es2_common.fs.glsl
@@ -1,17 +1,105 @@
 precision mediump float;
 
-uniform mat4 uMVP;
-uniform sampler2D uSource;
-uniform sampler2D uMask;
-uniform float uAlpha;
+uniform sampler2D u_source;
+uniform sampler2D u_mask;
+uniform mat4 u_projection;
+uniform mat4 u_modelview;
+uniform float u_alpha;
 uniform int uBlendMode;
+uniform vec4 u_viewport;
+
+// In GtkSnapshot coordinates
+uniform vec4 u_clip;
+uniform vec4 u_clip_corner_widths;
+uniform vec4 u_clip_corner_heights;
 
 varying vec2 vUv;
 
+
+struct RoundedRect
+{
+  vec4 bounds;
+  vec4 corner_widths;
+  vec4 corner_heights;
+};
+
+float
+ellipsis_dist (vec2 p, vec2 radius)
+{
+  if (radius == vec2(0, 0))
+    return 0.0;
+
+  vec2 p0 = p / radius;
+  vec2 p1 = 2.0 * p0 / radius;
+
+  return (dot(p0, p0) - 1.0) / length (p1);
+}
+
+float
+ellipsis_coverage (vec2 point, vec2 center, vec2 radius)
+{
+  float d = ellipsis_dist (point - center, radius);
+  return clamp (0.5 - d, 0.0, 1.0);
+}
+
+float
+rounded_rect_coverage (RoundedRect r, vec2 p)
+{
+  if (p.x < r.bounds.x || p.y < r.bounds.y ||
+      p.x >= r.bounds.z || p.y >= r.bounds.w)
+    return 0.0;
+
+  vec2 rad_tl = vec2(r.corner_widths.x, r.corner_heights.x);
+  vec2 rad_tr = vec2(r.corner_widths.y, r.corner_heights.y);
+  vec2 rad_br = vec2(r.corner_widths.z, r.corner_heights.z);
+  vec2 rad_bl = vec2(r.corner_widths.w, r.corner_heights.w);
+
+  vec2 ref_tl = r.bounds.xy + vec2( r.corner_widths.x,  r.corner_heights.x);
+  vec2 ref_tr = r.bounds.zy + vec2(-r.corner_widths.y,  r.corner_heights.y);
+  vec2 ref_br = r.bounds.zw + vec2(-r.corner_widths.z, -r.corner_heights.z);
+  vec2 ref_bl = r.bounds.xw + vec2( r.corner_widths.w, -r.corner_heights.w);
+
+  float d_tl = ellipsis_coverage(p, ref_tl, rad_tl);
+  float d_tr = ellipsis_coverage(p, ref_tr, rad_tr);
+  float d_br = ellipsis_coverage(p, ref_br, rad_br);
+  float d_bl = ellipsis_coverage(p, ref_bl, rad_bl);
+
+  vec4 corner_coverages = 1.0 - vec4(d_tl, d_tr, d_br, d_bl);
+
+  bvec4 is_out = bvec4(p.x < ref_tl.x && p.y < ref_tl.y,
+                       p.x > ref_tr.x && p.y < ref_tr.y,
+                       p.x > ref_br.x && p.y > ref_br.y,
+                       p.x < ref_bl.x && p.y > ref_bl.y);
+
+  return 1.0 - dot(vec4(is_out), corner_coverages);
+}
+
+RoundedRect
+rounded_rect_shrink (RoundedRect r, vec4 amount)
+{
+  vec4 new_bounds = r.bounds + vec4(1.0,1.0,-1.0,-1.0) * amount.wxyz;
+  vec4 new_widths = max (r.corner_widths - amount.wyyw, 0.0);
+  vec4 new_heights = max (r.corner_heights - amount.xxzz, 0.0);
+
+  return RoundedRect (new_bounds, new_widths, new_heights);
+}
+
 vec4 Texture(sampler2D sampler, vec2 texCoords) {
   return texture2D(sampler, texCoords);
 }
 
 void setOutputColor(vec4 color) {
-  gl_FragColor = color;
+  vec4 clipBounds = u_clip;
+  vec4 f = gl_FragCoord;
+
+  f.x += u_viewport.x;
+  f.y = (u_viewport.y + u_viewport.w) - f.y;
+
+  clipBounds.z = clipBounds.x + clipBounds.z;
+  clipBounds.w = clipBounds.y + clipBounds.w;
+
+  RoundedRect r = RoundedRect(clipBounds, u_clip_corner_widths, u_clip_corner_heights);
+
+  gl_FragColor = color * rounded_rect_coverage(r, f.xy);
+  /*gl_FragColor = color;*/
 }
diff --git a/gsk/resources/glsl/es2_common.vs.glsl b/gsk/resources/glsl/es2_common.vs.glsl
index 3db2e4d..c39fc44 100644
--- a/gsk/resources/glsl/es2_common.vs.glsl
+++ b/gsk/resources/glsl/es2_common.vs.glsl
@@ -1,4 +1,7 @@
-uniform mat4 uMVP;
+precision mediump float;
+
+uniform mat4 u_projection;
+uniform mat4 u_modelview;
 
 attribute vec2 aPosition;
 attribute vec2 aUv;
diff --git a/gsk/resources/glsl/outset_shadow.fs.glsl b/gsk/resources/glsl/outset_shadow.fs.glsl
index 63351b0..9a97c34 100644
--- a/gsk/resources/glsl/outset_shadow.fs.glsl
+++ b/gsk/resources/glsl/outset_shadow.fs.glsl
@@ -1,6 +1,6 @@
 uniform vec4 u_outline;
-uniform vec4 u_corner_widths = vec4(0, 0, 0, 0);
-uniform vec4 u_corner_heights = vec4(0, 0, 0, 0);
+uniform vec4 u_corner_widths;//= vec4(0, 0, 0, 0);
+uniform vec4 u_corner_heights;// = vec4(0, 0, 0, 0);
 
 void main() {
   vec4 f = gl_FragCoord;
@@ -11,6 +11,6 @@ void main() {
   RoundedRect outline = RoundedRect(vec4(u_outline.xy, u_outline.xy + u_outline.zw), u_corner_widths, 
u_corner_heights);
 
   vec4 color = Texture(u_source, vUv);
-  color = color * (1 -  clamp(rounded_rect_coverage (outline, f.xy), 0, 1));
+  color = color * (1.0 -  clamp(rounded_rect_coverage (outline, f.xy), 0.0, 1.0));
   setOutputColor(color * u_alpha);
 }