Added workarounds for some mobile GPUs which do not support all OpenGL operations when using the BGRA pixel format

es-core/src/components/ImageComponent.cpp

@@ -462,6 +462,15 @@ void ImageComponent::render(const glm::mat4& parentTrans)
             }
 
             mVertices->shaderFlags = mVertices->shaderFlags | Renderer::ShaderFlags::PREMULTIPLIED;
+
+#if defined(USE_OPENGLES)
+            // This is required as not all mobile GPUs support mipmapping when using the BGRA
+            // pixel format.
+            if (mMipmapping)
+                mVertices->shaderFlags =
+                    mVertices->shaderFlags | Renderer::ShaderFlags::CONVERT_PIXEL_FORMAT;
+#endif
+
             mRenderer->drawTriangleStrips(&mVertices[0], 4);
         }
         else {

es-core/src/renderers/Renderer.h

@@ -55,7 +55,8 @@ public:
         CLIPPING              = 0x00000008,
         ROTATED               = 0x00000010, // Screen rotated 90 or 270 degrees.
         ROUNDED_CORNERS       = 0x00000020,
-        ROUNDED_CORNERS_NO_AA = 0x00000040
+        ROUNDED_CORNERS_NO_AA = 0x00000040,
+        CONVERT_PIXEL_FORMAT  = 0x00000080
     };
     // clang-format on
 

es-core/src/renderers/RendererOpenGL.cpp

@@ -439,8 +439,16 @@ unsigned int RendererOpenGL::createTexture(const unsigned int texUnit,
                                                    static_cast<GLfloat>(GL_NEAREST)));
 
 #if defined(USE_OPENGLES)
-    GL_CHECK_ERROR(glTexImage2D(GL_TEXTURE_2D, 0, textureType, width, height, 0, textureType,
+    if (mipmapping) {
-                                GL_UNSIGNED_BYTE, data));
+        // This is required as not all mobile GPUs support mipmapping when using the BGRA
+        // pixel format.
+        GL_CHECK_ERROR(glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA,
+                                    GL_UNSIGNED_BYTE, data));
+    }
+    else {
+        GL_CHECK_ERROR(glTexImage2D(GL_TEXTURE_2D, 0, textureType, width, height, 0, textureType,
+                                    GL_UNSIGNED_BYTE, data));
+    }
 #else
     GL_CHECK_ERROR(glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, textureType,
                                 GL_UNSIGNED_BYTE, data));
@@ -644,6 +652,13 @@ void RendererOpenGL::shaderPostprocessing(unsigned int shaders,
     vertices->blurStrength = parameters.blurStrength;
     vertices->shaderFlags = ShaderFlags::POST_PROCESSING | ShaderFlags::PREMULTIPLIED;
 
+#if defined(USE_OPENGLES)
+    // This is required as not all mobile GPUs support the glReadPixels() function when using
+    // the BGRA pixel format.
+    if (textureRGBA)
+        vertices->shaderFlags |= ShaderFlags::CONVERT_PIXEL_FORMAT;
+#endif
+
     if (screenRotation == 90 || screenRotation == 270)
         vertices->shaderFlags |= ShaderFlags::ROTATED;
 
@@ -774,10 +789,10 @@ void RendererOpenGL::shaderPostprocessing(unsigned int shaders,
 #if defined(USE_OPENGLES)
         if (screenRotation == 0 || screenRotation == 180)
             GL_CHECK_ERROR(
-                glReadPixels(0, 0, width, height, GL_BGRA_EXT, GL_UNSIGNED_BYTE, textureRGBA));
+                glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, textureRGBA));
         else
             GL_CHECK_ERROR(
-                glReadPixels(0, 0, height, width, GL_BGRA_EXT, GL_UNSIGNED_BYTE, textureRGBA));
+                glReadPixels(0, 0, height, width, GL_RGBA, GL_UNSIGNED_BYTE, textureRGBA));
 #else
         if (screenRotation == 0 || screenRotation == 180)
             GL_CHECK_ERROR(

resources/shaders/glsl/blur_horizontal.glsl

@@ -41,6 +41,7 @@ out vec4 FragColor;
 // 0x00000010 - Screen rotated 90 or 270 degrees
 // 0x00000020 - Rounded corners
 // 0x00000040 - Rounded corners with no anti-aliasing
+// 0x00000080 - Convert pixel format
 
 void main()
 {

resources/shaders/glsl/blur_vertical.glsl

@@ -41,6 +41,7 @@ out vec4 FragColor;
 // 0x00000010 - Screen rotated 90 or 270 degrees
 // 0x00000020 - Rounded corners
 // 0x00000040 - Rounded corners with no anti-aliasing
+// 0x00000080 - Convert pixel format
 
 void main()
 {

resources/shaders/glsl/core.glsl

@@ -59,6 +59,7 @@ out vec4 FragColor;
 // 0x00000010 - Screen rotated 90 or 270 degrees
 // 0x00000020 - Rounded corners
 // 0x00000040 - Rounded corners with no anti-aliasing
+// 0x00000080 - Convert pixel format
 
 void main()
 {
@@ -74,7 +75,14 @@ void main()
             discard;
     }
 
-    vec4 sampledColor = texture(textureSampler0, texCoord);
+    vec4 sampledColor;
+
+    // Pixel format conversion is sometimes required as not all mobile GPUs support all
+    // OpenGL operations in BGRA format.
+    if (0x0u != (shaderFlags & 0x80u))
+        sampledColor.bgra = texture(textureSampler0, texCoord);
+    else
+        sampledColor = texture(textureSampler0, texCoord);
 
     // Rounded corners.
     if (0x0u != (shaderFlags & 0x20u) || 0x0u != (shaderFlags & 0x40u)) {

resources/shaders/glsl/scanlines.glsl

@@ -102,6 +102,7 @@ uniform float OutputGamma;
 // 0x00000010 - Screen rotated 90 or 270 degrees
 // 0x00000020 - Rounded corners
 // 0x00000040 - Rounded corners with no anti-aliasing
+// 0x00000080 - Convert pixel format
 
 void main()
 {