Use a macro TEX_SAMPLE() to replace the different texture sampling fu…

…nctions for WR_FEATURE_TEXTURE_EXTERNAL and WR_FEATURE_TEXTURE_RECT features.

webrender/res/ps_image.fs.glsl

@@ -28,15 +28,5 @@ void main(void) {
 
     alpha = alpha * float(all(bvec2(step(position_in_tile, vStretchSize))));
 
-#if defined(WR_FEATURE_TEXTURE_EXTERNAL) || defined(WR_FEATURE_TEXTURE_RECT)
-    // The textureLod() doesn't support samplerExternalOES.
-    // https://www.khronos.org/registry/OpenGL/extensions/OES/OES_EGL_image_external_essl3.txt
-    //
-    // The textureLod() doesn't support sampler2DRect, too.
-    //
-    // Use texture() instead.
-    oFragColor = vec4(alpha) * texture(sColor0, st);
-#else
-    oFragColor = vec4(alpha) * textureLod(sColor0, st, 0.0);
-#endif
+    oFragColor = vec4(alpha) * TEX_SAMPLE(sColor0, st);
 }

webrender/res/ps_yuv_image.fs.glsl

@@ -64,32 +64,15 @@ void main(void) {
 
     vec3 yuv_value;
 #ifdef WR_FEATURE_NV12
-    #if defined(WR_FEATURE_TEXTURE_EXTERNAL) || defined(WR_FEATURE_TEXTURE_RECT)
-        // The textureLod() doesn't support samplerExternalOES.
-        // https://www.khronos.org/registry/OpenGL/extensions/OES/OES_EGL_image_external_essl3.txt
-        //
-        // The textureLod() doesn't support sampler2DRect, too.
-        //
-        // Use texture() instead.
-        yuv_value.x = texture(sColor0, st_y).r;
-        yuv_value.yz = texture(sColor1, st_u).rg;
-    #else
-        yuv_value.x = textureLod(sColor0, st_y, 0.0).r;
-        yuv_value.yz = textureLod(sColor1, st_u, 0.0).rg;
-    #endif
+    yuv_value.x = TEX_SAMPLE(sColor0, st_y).r;
+    yuv_value.yz = TEX_SAMPLE(sColor1, st_u).rg;
 #else
     // The yuv_planar format should have this third texture coordinate.
     vec2 st_v = vTextureOffsetV + uv_offset;
 
-    #if defined(WR_FEATURE_TEXTURE_EXTERNAL) || defined(WR_FEATURE_TEXTURE_RECT)
-        yuv_value.x = texture(sColor0, st_y).r;
-        yuv_value.y = texture(sColor1, st_u).r;
-        yuv_value.z = texture(sColor2, st_v).r;
-    #else
-        yuv_value.x = textureLod(sColor0, st_y, 0.0).r;
-        yuv_value.y = textureLod(sColor1, st_u, 0.0).r;
-        yuv_value.z = textureLod(sColor2, st_v, 0.0).r;
-    #endif
+    yuv_value.x = TEX_SAMPLE(sColor0, st_y).r;
+    yuv_value.y = TEX_SAMPLE(sColor1, st_u).r;
+    yuv_value.z = TEX_SAMPLE(sColor2, st_v).r;
 #endif
 
     // See the YuvColorMatrix definition for an explanation of where the constants come from.

webrender/res/shared.glsl

@@ -8,6 +8,19 @@
 #extension GL_OES_EGL_image_external_essl3 : require
 #endif
 
+// The textureLod() doesn't support samplerExternalOES for WR_FEATURE_TEXTURE_EXTERNAL.
+// https://www.khronos.org/registry/OpenGL/extensions/OES/OES_EGL_image_external_essl3.txt
+//
+// The textureLod() doesn't support sampler2DRect for WR_FEATURE_TEXTURE_RECT, too.
+//
+// Use texture() instead.
+#if defined(WR_FEATURE_TEXTURE_EXTERNAL) || defined(WR_FEATURE_TEXTURE_RECT)
+#define TEX_SAMPLE(sampler, tex_coord) texture(sampler, tex_coord)
+#else
+// In normal case, we use textureLod(). We haven't used the lod yet. So, we always pass 0.0 now.
+#define TEX_SAMPLE(sampler, tex_coord) textureLod(sampler, tex_coord, 0.0)
+#endif
+
 //======================================================================================
 // Vertex shader attributes and uniforms
 //======================================================================================