Implement the pixelate effect

Author: adazem009

src/shadermanager.cpp

@@ -36,35 +36,27 @@ static const char *TEXTURE_UNIT_UNIFORM = "u_skin";
 static const char *SKIN_SIZE_UNIFORM = "u_skinSize";
 
 static const std::unordered_map<ShaderManager::Effect, const char *> EFFECT_TO_NAME = {
-    { ShaderManager::Effect::Color, "color" },
-    { ShaderManager::Effect::Brightness, "brightness" },
-    { ShaderManager::Effect::Ghost, "ghost" },
-    { ShaderManager::Effect::Fisheye, "fisheye" },
-    { ShaderManager::Effect::Whirl, "whirl" }
+    { ShaderManager::Effect::Color, "color" },     { ShaderManager::Effect::Brightness, "brightness" }, { ShaderManager::Effect::Ghost, "ghost" },
+    { ShaderManager::Effect::Fisheye, "fisheye" }, { ShaderManager::Effect::Whirl, "whirl" },           { ShaderManager::Effect::Pixelate, "pixelate" }
 };
 
 static const std::unordered_map<ShaderManager::Effect, const char *> EFFECT_UNIFORM_NAME = {
-    { ShaderManager::Effect::Color, "u_color" },
-    { ShaderManager::Effect::Brightness, "u_brightness" },
-    { ShaderManager::Effect::Ghost, "u_ghost" },
-    { ShaderManager::Effect::Fisheye, "u_fisheye" },
-    { ShaderManager::Effect::Whirl, "u_whirl" }
+    { ShaderManager::Effect::Color, "u_color" },     { ShaderManager::Effect::Brightness, "u_brightness" }, { ShaderManager::Effect::Ghost, "u_ghost" },
+    { ShaderManager::Effect::Fisheye, "u_fisheye" }, { ShaderManager::Effect::Whirl, "u_whirl" },           { ShaderManager::Effect::Pixelate, "u_pixelate" }
 };
 
 static const std::unordered_map<ShaderManager::Effect, ConverterFunc> EFFECT_CONVERTER = {
     { ShaderManager::Effect::Color, [](float x) { return wrapClamp(x / 200.0f, 0.0f, 1.0f); } },
     { ShaderManager::Effect::Brightness, [](float x) { return std::clamp(x, -100.0f, 100.0f) / 100.0f; } },
     { ShaderManager::Effect::Ghost, [](float x) { return 1 - std::clamp(x, 0.0f, 100.0f) / 100.0f; } },
     { ShaderManager::Effect::Fisheye, [](float x) { return std::max(0.0f, (x + 100.0f) / 100.0f); } },
-    { ShaderManager::Effect::Whirl, [](float x) { return x * (float)pi / 180.0f; } }
+    { ShaderManager::Effect::Whirl, [](float x) { return x * (float)pi / 180.0f; } },
+    { ShaderManager::Effect::Pixelate, [](float x) { return std::abs(x) / 10.0f; } }
 };
 
 static const std::unordered_map<ShaderManager::Effect, bool> EFFECT_SHAPE_CHANGES = {
-    { ShaderManager::Effect::Color, false },
-    { ShaderManager::Effect::Brightness, false },
-    { ShaderManager::Effect::Ghost, false },
-    { ShaderManager::Effect::Fisheye, true },
-    { ShaderManager::Effect::Whirl, true }
+    { ShaderManager::Effect::Color, false },  { ShaderManager::Effect::Brightness, false }, { ShaderManager::Effect::Ghost, false },
+    { ShaderManager::Effect::Fisheye, true }, { ShaderManager::Effect::Whirl, true },       { ShaderManager::Effect::Pixelate, true }
 };
 
 Q_GLOBAL_STATIC(ShaderManager, globalInstance)

src/shaders/sprite.frag

@@ -26,6 +26,11 @@ uniform float u_fisheye;
 uniform float u_whirl;
 #endif // ENABLE_whirl
 
+#ifdef ENABLE_pixelate
+uniform float u_pixelate;
+uniform vec2 u_skinSize;
+#endif // ENABLE_pixelate
+
 varying vec2 v_texCoord;
 uniform sampler2D u_skin;
 
@@ -97,6 +102,14 @@ void main()
 {
     vec2 texcoord0 = v_texCoord;
 
+    #ifdef ENABLE_pixelate
+    {
+        // TODO: clean up "pixel" edges
+        vec2 pixelTexelSize = u_skinSize / u_pixelate;
+        texcoord0 = (floor(texcoord0 * pixelTexelSize) + kCenter) / pixelTexelSize;
+    }
+    #endif // ENABLE_pixelate
+
     #ifdef ENABLE_whirl
     {
         const float kRadius = 0.5;

test/penlayer/penlayer_test.cpp

@@ -393,6 +393,7 @@ TEST_F(PenLayerTest, Stamp)
         targets.back()->updateCostume(sprite->sprite()->currentCostume().get());
         targets.back()->setGraphicEffect(ShaderManager::Effect::Color, i * 25);
         targets.back()->setGraphicEffect(ShaderManager::Effect::Ghost, i * 5);
+        targets.back()->setGraphicEffect(ShaderManager::Effect::Pixelate, i * 25);
         sprite->setRenderedTarget(targets.back().get());
         i++;
     }

test/shape_changing_effects.png

@@ -111,8 +111,8 @@ TEST_F(TargetPainterTest, Paint)
     effects.clear();
     effects[ShaderManager::Effect::Fisheye] = 46;
     effects[ShaderManager::Effect::Whirl] = 50;
-    /*effects[ShaderManager::Effect::Pixelate] = 25;
-    effects[ShaderManager::Effect::Mosaic] = 30;*/
+    effects[ShaderManager::Effect::Pixelate] = 25;
+    // effects[ShaderManager::Effect::Mosaic] = 30;
     EXPECT_CALL(target, texture()).WillOnce(Return(texture));
     EXPECT_CALL(target, cpuTexture()).WillOnce(ReturnRef(texture));
     EXPECT_CALL(target, graphicEffects()).WillOnce(ReturnRef(effects));