blur: optimize coordinates calculations

Save 28 instructions on i915 (mainly redundant MOVs) and gain a 25%
(roughly measured with videotestsrc and glimagesink sync=false) speed
bump

1 files changed, 19 insertions, 23 deletions

diff --git a/gst/gl/effects/gstgleffectssources.c b/gst/gl/effects/gstgleffectssources.c
index b26be16..20c4ba5 100644
--- a/gst/gl/effects/gstgleffectssources.c
+++ b/gst/gl/effects/gstgleffectssources.c
@@ -390,17 +390,15 @@ const gchar *hconv9_fragment_source =
   "uniform float kernel[9];"
   "void main () {"
   "  vec2 texturecoord[9];"
-  "  float s = gl_TexCoord[0].s;"
-  "  float t = gl_TexCoord[0].t;"
-  "  texturecoord[0] = vec2(s-4.0, t);"
-  "  texturecoord[1] = vec2(s-3.0, t);"
-  "  texturecoord[2] = vec2(s-2.0, t);"
-  "  texturecoord[3] = vec2(s-1.0, t);"
-  "  texturecoord[4] = vec2(s, t);"
-  "  texturecoord[5] = vec2(s+1.0, t);"
-  "  texturecoord[6] = vec2(s+2.0, t);"
-  "  texturecoord[7] = vec2(s+3.0, t);"
-  "  texturecoord[8] = vec2(s+4.0, t);"
+  "  texturecoord[4] = gl_TexCoord[0].st;"
+  "  texturecoord[3] = texturecoord[4] - vec2(1.0, 0.0);"
+  "  texturecoord[2] = texturecoord[3] - vec2(1.0, 0.0);"
+  "  texturecoord[1] = texturecoord[2] - vec2(1.0, 0.0);"
+  "  texturecoord[0] = texturecoord[1] - vec2(1.0, 0.0);"
+  "  texturecoord[5] = texturecoord[4] + vec2(1.0, 0.0);"
+  "  texturecoord[6] = texturecoord[5] + vec2(1.0, 0.0);"
+  "  texturecoord[7] = texturecoord[6] + vec2(1.0, 0.0);"
+  "  texturecoord[8] = texturecoord[7] + vec2(1.0, 0.0);"
   "  int i;"
   "  vec4 sum = vec4 (0.0);"
   "  for (i = 0; i < 9; i++) { "
@@ -417,22 +415,20 @@ const gchar *vconv9_fragment_source =
   "uniform float kernel[9];"
   "void main () {"
   "  vec2 texturecoord[9];"
-  "  float s = gl_TexCoord[0].s;"
-  "  float t = gl_TexCoord[0].t;"
-  "  texturecoord[0] = vec2(s, t-4.0);"
-  "  texturecoord[1] = vec2(s, t-3.0);"
-  "  texturecoord[2] = vec2(s, t-2.0);"
-  "  texturecoord[3] = vec2(s, t-1.0);"
-  "  texturecoord[4] = vec2(s, t);"
-  "  texturecoord[5] = vec2(s, t+1.0);"
-  "  texturecoord[6] = vec2(s, t+2.0);"
-  "  texturecoord[7] = vec2(s, t+3.0);"
-  "  texturecoord[8] = vec2(s, t+4.0);"
+  "  texturecoord[4] = gl_TexCoord[0].st;"
+  "  texturecoord[3] = texturecoord[4] - vec2(0.0, 1.0);"
+  "  texturecoord[2] = texturecoord[3] - vec2(0.0, 1.0);"
+  "  texturecoord[1] = texturecoord[2] - vec2(0.0, 1.0);"
+  "  texturecoord[0] = texturecoord[1] - vec2(0.0, 1.0);"
+  "  texturecoord[5] = texturecoord[4] + vec2(0.0, 1.0);"
+  "  texturecoord[6] = texturecoord[5] + vec2(0.0, 1.0);"
+  "  texturecoord[7] = texturecoord[6] + vec2(0.0, 1.0);"
+  "  texturecoord[8] = texturecoord[7] + vec2(0.0, 1.0);"
   "  int i;"
   "  vec4 sum = vec4 (0.0);"
   "  for (i = 0; i < 9; i++) { "
   "    vec4 neighbor = texture2DRect(tex, texturecoord[i]);"
-  "    sum += neighbor * kernel[i]; "
+  "    sum += neighbor * kernel[i];"
   "  }"
   "  gl_FragColor = sum;"
   "}";