[sdl] Use PMA asset in example, formatting, port to C backend

examples/export/runtimes.sh

@@ -225,8 +225,8 @@ cp -f ../celestial-circus/export/celestial-circus.png "$ROOT/spine-godot/example
 echo "spine-sdl"
 rm -f "$ROOT/spine-sdl/data/"*
 cp -f ../spineboy/export/spineboy-pro.json "$ROOT/spine-sdl/data/"
-cp -f ../spineboy/export/spineboy.atlas "$ROOT/spine-sdl/data/"
+cp -f ../spineboy/export/spineboy-pma.atlas "$ROOT/spine-sdl/data/"
-cp -f ../spineboy/export/spineboy.png "$ROOT/spine-sdl/data/"
+cp -f ../spineboy/export/spineboy-pma.png "$ROOT/spine-sdl/data/"
 
 echo "spine-sfml-c"
 rm "$ROOT/spine-sfml/c/data/"*

spine-sdl/README.md

@@ -20,7 +20,7 @@ For the official legal terms governing the Spine Runtimes, please read the [Spin
 
 spine-sdl works with data exported from Spine 4.2.xx.
 
-spine-sdl supports all Spine features except premultiplied alpha, screen blend mode, and two color tinting.
+spine-sdl supports all Spine features except screen blend mode and two color tinting.
 
 ## Usage
 

spine-sdl/data/spineboy-pma.atlas

@@ -1,6 +1,7 @@
-spineboy.png
+spineboy-pma.png
 	size: 1024, 256
 	filter: Linear, Linear
+	pma: true
 	scale: 0.5
 crosshair
 	bounds: 352, 7, 45, 45

spine-sdl/example/main.c

@@ -47,13 +47,14 @@ int main() {
 		return -1;
 	}
 
-	spAtlas *atlas = spAtlas_createFromFile("data/spineboy.atlas", renderer);
+	spAtlas *atlas = spAtlas_createFromFile("data/spineboy-pma.atlas", renderer);
 	spSkeletonJson *json = spSkeletonJson_create(atlas);
 	json->scale = 0.5f;
 	spSkeletonData *skeletonData = spSkeletonJson_readSkeletonDataFile(json, "data/spineboy-pro.json");
 	spAnimationStateData *animationStateData = spAnimationStateData_create(skeletonData);
 	animationStateData->defaultMix = 0.2f;
 	spSkeletonDrawable *drawable = spSkeletonDrawable_create(skeletonData, animationStateData);
+    drawable->usePremultipliedAlpha = -1;
 	drawable->skeleton->x = 400;
 	drawable->skeleton->y = 500;
 	spSkeleton_setToSetupPose(drawable->skeleton);

spine-sdl/example/main.cpp

@@ -48,12 +48,13 @@ int main(int argc, char **argv) {
 	}
 
 	spine::SDLTextureLoader textureLoader(renderer);
-	spine::Atlas atlas("data/spineboy.atlas", &textureLoader);
+	spine::Atlas atlas("data/spineboy-pma.atlas", &textureLoader);
 	spine::AtlasAttachmentLoader attachmentLoader(&atlas);
 	spine::SkeletonJson json(&attachmentLoader);
 	json.setScale(0.5f);
 	spine::SkeletonData *skeletonData = json.readSkeletonDataFile("data/spineboy-pro.json");
 	spine::SkeletonDrawable drawable(skeletonData);
+    drawable.usePremultipliedAlpha = true;
 	drawable.animationState->getData()->setDefaultMix(0.2f);
 	drawable.skeleton->setPosition(400, 500);
 	drawable.skeleton->setToSetupPose();

spine-sdl/src/spine-sdl-c.c

@@ -42,6 +42,7 @@ spSkeletonDrawable *spSkeletonDrawable_create(spSkeletonData *skeletonData, spAn
 	spSkeletonDrawable *self = NEW(spSkeletonDrawable);
 	self->skeleton = spSkeleton_create(skeletonData);
 	self->animationState = spAnimationState_create(animationStateData);
+    self->usePremultipliedAlpha = 0;
 	self->sdlIndices = spIntArray_create(12);
 	self->sdlVertices = spSdlVertexArray_create(12);
 	self->worldVertices = spFloatArray_create(12);
@@ -163,6 +164,7 @@ void spSkeletonDrawable_draw(spSkeletonDrawable *self, struct SDL_Renderer *rend
 		for (int ii = 0; ii < (int) indicesCount; ii++)
 			spIntArray_add(self->sdlIndices, indices[ii]);
 
+        if (!self->usePremultipliedAlpha) {
             switch (slot->data->blendMode) {
                 case SP_BLEND_MODE_NORMAL:
                     SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_BLEND);
@@ -176,6 +178,26 @@ void spSkeletonDrawable_draw(spSkeletonDrawable *self, struct SDL_Renderer *rend
                 case SP_BLEND_MODE_SCREEN:
                     SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_BLEND);
                     break;
+            }
+        } else {
+            SDL_BlendMode target;
+            switch (slot->data->blendMode) {
+                case SP_BLEND_MODE_NORMAL:
+                    target = SDL_ComposeCustomBlendMode(SDL_BLENDFACTOR_ONE, SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA, SDL_BLENDOPERATION_ADD, SDL_BLENDFACTOR_ONE, SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA, SDL_BLENDOPERATION_ADD);
+                    SDL_SetTextureBlendMode(texture, target);
+                    break;
+                case SP_BLEND_MODE_MULTIPLY:
+                    SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_MOD);
+                    break;
+                case SP_BLEND_MODE_ADDITIVE:
+                    target = SDL_ComposeCustomBlendMode(SDL_BLENDFACTOR_ONE, SDL_BLENDFACTOR_ONE, SDL_BLENDOPERATION_ADD, SDL_BLENDFACTOR_ONE, SDL_BLENDFACTOR_ONE, SDL_BLENDOPERATION_ADD);
+                    SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_ADD);
+                    break;
+                case SP_BLEND_MODE_SCREEN:
+                    target = SDL_ComposeCustomBlendMode(SDL_BLENDFACTOR_ONE, SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA, SDL_BLENDOPERATION_ADD, SDL_BLENDFACTOR_ONE, SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA, SDL_BLENDOPERATION_ADD);
+                    SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_BLEND);
+                    break;
+            }
         }
 
 		SDL_RenderGeometry(renderer, texture, self->sdlVertices->items, self->sdlVertices->size, self->sdlIndices->items,

spine-sdl/src/spine-sdl-c.h

@@ -43,6 +43,7 @@ _SP_ARRAY_DECLARE_TYPE(spSdlVertexArray, struct SDL_Vertex)
 typedef struct spSkeletonDrawable {
 	spSkeleton *skeleton;
 	spAnimationState *animationState;
+    int usePremultipliedAlpha;
 
 	spSkeletonClipping *clipper;
 	spFloatArray *worldVertices;

spine-sdl/src/spine-sdl-cpp.cpp

@@ -177,8 +177,7 @@ void SkeletonDrawable::draw(SDL_Renderer *renderer) {
 					SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_BLEND);
 					break;
 			}
-		}
+		} else {
-		else {
 			SDL_BlendMode target;
 			switch (slot.getData().getBlendMode()) {
 				case BlendMode_Normal:

spine-sdl/src/spine-sdl-cpp.h

@@ -46,9 +46,7 @@ namespace spine {
 
 		Skeleton *skeleton;
 		AnimationState *animationState;
-
+        bool usePremultipliedAlpha;
-		void setUsePremultipliedAlpha(bool usePMA) { usePremultipliedAlpha = usePMA; };
-		bool getUsePremultipliedAlpha() { return usePremultipliedAlpha; };
 
 	private:
 		bool ownsAnimationStateData;
@@ -56,7 +54,6 @@ namespace spine {
 		Vector<float> worldVertices;
 		Vector<SDL_Vertex> sdlVertices;
 		Vector<int> sdlIndices;
-		bool usePremultipliedAlpha;
 	};
 
 	class SDLTextureLoader : public spine::TextureLoader {