[gl canvas] allow multiple textures per batch

src/gl_canvas.c

@@ -30,7 +30,8 @@ typedef struct mg_gl_path
 	vec4 box;
 	vec4 clip;
 	mg_gl_cmd cmd;
-	u8 pad[12];
+	int textureID;
+	u8 pad[8];
 } mg_gl_path;
 
 enum _mg_gl_seg_kind{
@@ -125,6 +126,7 @@ enum {
 	MG_GL_INPUT_BUFFERS_COUNT = 3,
 	MG_GL_TILE_SIZE = 16,
 	MG_GL_MSAA_COUNT = 8,
+	MG_GL_MAX_IMAGES_PER_BATCH = 8,
 };
 
 typedef struct mg_gl_mapped_buffer
@@ -186,6 +188,7 @@ typedef struct mg_gl_canvas_backend
 	int maxTileQueueCount;
 	int maxSegmentCount;
 
+	int currentImageIndex;
 } mg_gl_canvas_backend;
 
 static void mg_update_path_extents(vec4* extents, vec2 p)
@@ -362,6 +365,12 @@ void mg_gl_canvas_encode_path(mg_gl_canvas_backend* backend, mg_primitive* primi
 		path->uvTransform[9] = uvTransform.m[5];
 		path->uvTransform[10] = 1;
 		path->uvTransform[11] = 0;
+
+		path->textureID = backend->currentImageIndex;
+	}
+	else
+	{
+		path->textureID = -1;
 	}
 
 	int nTilesX = ((path->box.z - path->box.x)*scale - 1) / MG_GL_TILE_SIZE + 1;
@@ -1043,7 +1052,7 @@ void mg_gl_grow_buffer_if_needed(GLuint buffer, i32 wantedSize, const char* name
 
 void mg_gl_render_batch(mg_gl_canvas_backend* backend,
                         mg_wgl_surface* surface,
-                        mg_image_data* image,
+                        mg_image* images,
                         int tileSize,
                         int nTilesX,
                         int nTilesY,
@@ -1220,18 +1229,7 @@ void mg_gl_render_batch(mg_gl_canvas_backend* backend,
 	glUniform1i(0, tileSize);
 	glUniform1f(1, scale);
 	glUniform1i(2, pathCount);
-
+	glUniform1i(3, backend->pathBatchStart);
-	// if there's an image, don't cull solid tiles
-	if(image)
-	{
-		glUniform1i(3, 0);
-	}
-	else
-	{
-		glUniform1i(3, 1);
-	}
-
-	glUniform1i(4, backend->pathBatchStart);
 
 	glDispatchCompute(nTilesX, nTilesY, 1);
 	glMemoryBarrier(GL_SHADER_STORAGE_BARRIER_BIT);
@@ -1269,20 +1267,21 @@ void mg_gl_render_batch(mg_gl_canvas_backend* backend,
 
 	glBindImageTexture(0, backend->outTexture, 0, GL_FALSE, 0, GL_WRITE_ONLY, GL_RGBA8);
 
+	for(int i=0; i<MG_GL_MAX_IMAGES_PER_BATCH; i++)
+	{
+		if(images[i].h)
+		{
+			mg_gl_image* image = (mg_gl_image*)mg_image_data_from_handle(images[i]);
 			if(image)
 			{
-		mg_gl_image* glImage = (mg_gl_image*)image;
+				glActiveTexture(GL_TEXTURE1+i);
-		glActiveTexture(GL_TEXTURE1);
+				glBindTexture(GL_TEXTURE_2D, image->texture);
-		glBindTexture(GL_TEXTURE_2D, glImage->texture);
+			}
-		glUniform1ui(2, 1);
 		}
-	else
-	{
-		glUniform1ui(2, 0);
 	}
 
-	glUniform1i(3, backend->pathBatchStart);
+	glUniform1i(2, backend->pathBatchStart);
-	glUniform1ui(4, maxWorkGroupCount);
+	glUniform1ui(3, maxWorkGroupCount);
 
 	glBindBuffer(GL_DISPATCH_INDIRECT_BUFFER, backend->rasterDispatchBuffer);
 	glDispatchComputeIndirect(0);
@@ -1397,28 +1396,53 @@ void mg_gl_canvas_render(mg_canvas_backend* interface,
 
 	//NOTE: encode and render batches
 	vec2 currentPos = {0};
-	mg_image currentImage = mg_image_nil();
+	mg_image images[MG_GL_MAX_IMAGES_PER_BATCH] = {0};
-
+	int imageCount = 0;
 	backend->eltCount = 0;
 
 	for(int primitiveIndex = 0; primitiveIndex < primitiveCount; primitiveIndex++)
 	{
 		mg_primitive* primitive = &primitives[primitiveIndex];
 
-		if(primitiveIndex && (primitive->attributes.image.h != currentImage.h))
+		if(primitive->attributes.image.h != 0)
+		{
+			backend->currentImageIndex = -1;
+			for(int i=0; i<imageCount; i++)
+			{
+				if(images[i].h == primitive->attributes.image.h)
+				{
+					backend->currentImageIndex = i;
+				}
+			}
+			if(backend->currentImageIndex <= 0)
+			{
+				if(imageCount<MG_GL_MAX_IMAGES_PER_BATCH)
+				{
+					images[imageCount] = primitive->attributes.image;
+					backend->currentImageIndex = imageCount;
+					imageCount++;
+				}
+				else
 				{
-			mg_image_data* imageData = mg_image_data_from_handle(currentImage);
-
 					mg_gl_render_batch(backend,
 					                    surface,
-			                   imageData,
+					                    images,
 					                    tileSize,
 					                    nTilesX,
 					                    nTilesY,
 					                    viewportSize,
 					                    scale);
+
+					images[0] = primitive->attributes.image;
+					backend->currentImageIndex = 0;
+					imageCount = 1;
+				}
+			}
+		}
+		else
+		{
+			backend->currentImageIndex = -1;
 		}
-		currentImage = primitive->attributes.image;
 
 		if(primitive->path.count)
 		{
@@ -1470,10 +1494,9 @@ void mg_gl_canvas_render(mg_canvas_backend* interface,
 		}
 	}
 
-	mg_image_data* imageData = mg_image_data_from_handle(currentImage);
 	mg_gl_render_batch(backend,
 	                    surface,
-	                    imageData,
+	                    images,
 	                    tileSize,
 	                    nTilesX,
 	                    nTilesY,
@@ -1661,10 +1684,10 @@ mg_canvas_backend* gl_canvas_backend_create(mg_wgl_surface* surface)
 
 		//NOTE(martin): setup interface functions
 		backend->interface.destroy = mg_gl_canvas_destroy;
+		backend->interface.render = mg_gl_canvas_render;
 		backend->interface.imageCreate = mg_gl_canvas_image_create;
 		backend->interface.imageDestroy = mg_gl_canvas_image_destroy;
 		backend->interface.imageUploadRegion = mg_gl_canvas_image_upload_region;
-		backend->interface.render = mg_gl_canvas_render;
 
 		surface->interface.prepare((mg_surface_data*)surface);
 

src/glsl_shaders/common.glsl

@@ -34,6 +34,7 @@ struct mg_gl_path
 	vec4 box;
 	vec4 clip;
 	int cmd;
+	int textureID;
 };
 
 struct mg_gl_path_elt

src/glsl_shaders/merge.glsl

@@ -43,8 +43,7 @@ layout(binding = 6) coherent restrict buffer screenTilesCountBufferSSBO
 layout(location = 0) uniform int tileSize;
 layout(location = 1) uniform float scale;
 layout(location = 2) uniform int pathCount;
-layout(location = 3) uniform int cullSolidTiles;
+layout(location = 3) uniform int pathBufferStart;
-layout(location = 4) uniform int pathBufferStart;
 
 void main()
 {
@@ -130,7 +129,7 @@ void main()
 						tileOpBuffer.elements[pathOpIndex].kind = MG_GL_OP_FILL;
 
 						if(  pathBuffer.elements[pathBufferStart + pathIndex].color.a == 1
-						  && cullSolidTiles != 0)
+						  && pathBuffer.elements[pathBufferStart + pathIndex].textureID < 0)
 						{
 							screenTilesBuffer.elements[tileIndex].first = pathOpIndex;
 						}

src/glsl_shaders/raster.glsl

@@ -32,12 +32,19 @@ layout(binding = 4) restrict readonly buffer screenTilesCountBufferSSBO
 
 layout(location = 0) uniform float scale;
 layout(location = 1) uniform int msaaSampleCount;
-layout(location = 2) uniform uint useTexture;
+layout(location = 2) uniform int pathBufferStart;
-layout(location = 3) uniform int pathBufferStart;
+layout(location = 3) uniform uint maxWorkGroupCount;
-layout(location = 4) uniform uint maxWorkGroupCount;
 
 layout(rgba8, binding = 0) uniform restrict writeonly image2D outTexture;
-layout(binding = 1) uniform sampler2D srcTexture;
+
+layout(binding = 1) uniform sampler2D srcTexture0;
+layout(binding = 2) uniform sampler2D srcTexture1;
+layout(binding = 3) uniform sampler2D srcTexture2;
+layout(binding = 4) uniform sampler2D srcTexture3;
+layout(binding = 5) uniform sampler2D srcTexture4;
+layout(binding = 6) uniform sampler2D srcTexture5;
+layout(binding = 7) uniform sampler2D srcTexture6;
+layout(binding = 8) uniform sampler2D srcTexture7;
 
 void main()
 {
@@ -146,15 +153,49 @@ void main()
 			vec4 nextColor = pathBuffer.elements[pathBufferStart + pathIndex].color;
 			nextColor.rgb *= nextColor.a;
 
-			if(useTexture != 0)
+			int textureID = pathBuffer.elements[pathBufferStart+pathIndex].textureID;
+			if(textureID >= 0)
 			{
 				vec4 texColor = vec4(0);
+
 				for(int sampleIndex = 0; sampleIndex<srcSampleCount; sampleIndex++)
 				{
 					vec2 sampleCoord = imgSampleCoords[sampleIndex];
 					vec3 ph = vec3(sampleCoord.xy, 1);
 					vec2 uv = (pathBuffer.elements[pathBufferStart + pathIndex].uvTransform * ph).xy;
-					texColor += texture(srcTexture, uv);
+
+					if(textureID == 0)
+					{
+						texColor += texture(srcTexture0, uv);
+					}
+					else if(textureID == 1)
+					{
+						texColor += texture(srcTexture1, uv);
+					}
+					else if(textureID == 2)
+					{
+						texColor += texture(srcTexture2, uv);
+					}
+					else if(textureID == 3)
+					{
+						texColor += texture(srcTexture3, uv);
+					}
+					else if(textureID == 4)
+					{
+						texColor += texture(srcTexture4, uv);
+					}
+					else if(textureID == 5)
+					{
+						texColor += texture(srcTexture5, uv);
+					}
+					else if(textureID == 6)
+					{
+						texColor += texture(srcTexture6, uv);
+					}
+					else if(textureID == 7)
+					{
+						texColor += texture(srcTexture7, uv);
+					}
 				}
 				texColor /= srcSampleCount;
 				texColor.rgb *= texColor.a;