ok just draw chunks twice, but with different scales, k

libcygnet/include/cygnet/shaders.h

@@ -5,9 +5,6 @@ namespace Cygnet::Shaders {
 extern const char *chunkVx;
 extern const char *chunkFr;
 
-extern const char *chunkShadowVx;
-extern const char *chunkShadowFr;
-
 extern const char *tileVx;
 extern const char *tileFr;
 

libcygnet/src/Renderer.cc

@@ -73,59 +73,6 @@ struct ChunkProg: public GlProgram {
 	}
 };
 
-struct ChunkShadowProg: public GlProgram {
-	template<typename... T>
-	ChunkShadowProg(const T &... shaders): GlProgram(shaders...) { init(); }
-	~ChunkShadowProg() { deinit(); }
-
-	GLint camera = uniformLoc("camera");
-	GLint pos = uniformLoc("pos");
-	GLint vertex = attribLoc("vertex");
-	GLint tex = uniformLoc("tex");
-
-	GLuint vbo;
-
-	static constexpr float ch = (float)SwanCommon::CHUNK_HEIGHT;
-	static constexpr float cw = (float)SwanCommon::CHUNK_WIDTH;
-	static constexpr GLfloat vertexes[] = {
-		0.0f,  0.0f, // pos 0: top left
-		0.0f,  ch ,  // pos 1: bottom left
-		cw,    ch,   // pos 2: bottom right
-		cw,    ch,   // pos 2: bottom right
-		cw,    0.0f, // pos 3: top right
-		0.0f,  0.0f, // pos 0: top left
-	};
-
-	void enable() {
-		glUseProgram(id());
-		glBindBuffer(GL_ARRAY_BUFFER, vbo);
-		glVertexAttribPointer(vertex, 2, GL_FLOAT, GL_FALSE, 0, (void *)0);
-		glEnableVertexAttribArray(vertex);
-		glCheck();
-
-		glUniform1i(tex, 0);
-	}
-
-	void disable() {
-		glDisableVertexAttribArray(vertex);
-		glCheck();
-	}
-
-	void init() {
-		glGenBuffers(1, &vbo);
-		glCheck();
-
-		glBindBuffer(GL_ARRAY_BUFFER, vbo);
-		glBufferData(GL_ARRAY_BUFFER, sizeof(vertexes), vertexes, GL_STATIC_DRAW);
-		glCheck();
-	}
-
-	void deinit() {
-		glDeleteBuffers(1, &vbo);
-		glCheck();
-	}
-};
-
 struct TileProg: public GlProgram {
 	template<typename... T>
 	TileProg(const T &... shaders): GlProgram(shaders...) { init(); }
@@ -337,8 +284,6 @@ struct BlendProg: public GlProgram {
 struct RendererState {
 	GlVxShader chunkVx{Shaders::chunkVx};
 	GlFrShader chunkFr{Shaders::chunkFr};
-	GlVxShader chunkShadowVx{Shaders::chunkShadowVx};
-	GlFrShader chunkShadowFr{Shaders::chunkShadowFr};
 	GlVxShader tileVx{Shaders::tileVx};
 	GlFrShader tileFr{Shaders::tileFr};
 	GlVxShader spriteVx{Shaders::spriteVx};
@@ -349,7 +294,6 @@ struct RendererState {
 	GlFrShader blendFr{Shaders::blendFr};
 
 	ChunkProg chunkProg{chunkVx, chunkFr};
-	ChunkShadowProg chunkShadowProg{chunkShadowVx, chunkShadowFr};
 	TileProg tileProg{tileVx, tileFr};
 	SpriteProg spriteProg{spriteVx, spriteFr};
 	RectProg rectProg{rectVx, rectFr};
@@ -358,6 +302,8 @@ struct RendererState {
 	SwanCommon::Vec2i screenSize;
 	GLuint offscreenFramebuffer = 0;
 	GLuint offscreenTex = 0;
+	GLuint opacityFramebuffer = 0;
+	GLuint opacityTex = 0;
 	GLuint atlasTex = 0;
 	SwanCommon::Vec2 atlasTexSize;
 };
@@ -366,8 +312,15 @@ Renderer::Renderer(): state_(std::make_unique<RendererState>()) {
 	glGenTextures(1, &state_->atlasTex);
 	glCheck();
 
+	glGenFramebuffers(1, &state_->offscreenFramebuffer);
+	glCheck();
 	glGenTextures(1, &state_->offscreenTex);
 	glCheck();
+
+	glGenFramebuffers(1, &state_->opacityFramebuffer);
+	glCheck();
+	glGenTextures(1, &state_->opacityTex);
+	glCheck();
 }
 
 Renderer::~Renderer() {
@@ -392,7 +345,6 @@ void Renderer::draw(const RenderCamera &cam) {
 	}
 
 	auto &chunkProg = state_->chunkProg;
-	auto &chunkShadowProg = state_->chunkShadowProg;
 	auto &tileProg = state_->tileProg;
 	auto &spriteProg = state_->spriteProg;
 	auto &rectProg = state_->rectProg;
@@ -400,6 +352,7 @@ void Renderer::draw(const RenderCamera &cam) {
 
 	if (state_->screenSize != cam.size) {
 		state_->screenSize = cam.size;
+
 		glBindTexture(GL_TEXTURE_2D, state_->offscreenTex);
 		glCheck();
 		glTexImage2D(
@@ -409,14 +362,47 @@ void Renderer::draw(const RenderCamera &cam) {
 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 		glCheck();
 
-		glGenFramebuffers(1, &state_->offscreenFramebuffer);
+		glBindTexture(GL_TEXTURE_2D, state_->opacityTex);
 		glCheck();
-		glBindFramebuffer(GL_FRAMEBUFFER, state_->offscreenFramebuffer);
+		glTexImage2D(
+				GL_TEXTURE_2D, 0, GL_RGBA, cam.size.x, cam.size.y, 0,
+				GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 		glCheck();
-		glFramebufferTexture2D(
-				GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
-				state_->offscreenTex, 0);
+	}
+
+	glBindFramebuffer(GL_FRAMEBUFFER, state_->opacityFramebuffer);
+	glFramebufferTexture2D(
+			GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
+			state_->opacityTex, 0);
+	glClearColor(0, 0, 0, 0);
+	glClear(GL_COLOR_BUFFER_BIT);
+	glCheck();
+
+	{
+		Mat3gf scaledCamMat = camMat;
+		scaledCamMat.scale({0.5, 0.5});
+		chunkProg.enable();
+		glUniformMatrix3fv(chunkProg.camera, 1, GL_TRUE, scaledCamMat.data());
+		glCheck();
+
+		glUniform2f(chunkProg.tileAtlasSize, state_->atlasTexSize.x, state_->atlasTexSize.y);
 		glCheck();
+
+		glActiveTexture(GL_TEXTURE0);
+		glBindTexture(GL_TEXTURE_2D, state_->atlasTex);
+		glCheck();
+
+		glActiveTexture(GL_TEXTURE1);
+		for (auto [pos, chunk]: drawChunks_) {
+			glUniform2f(chunkProg.pos, pos.x, pos.y);
+			glBindTexture(GL_TEXTURE_2D, chunk.tex);
+			glDrawArrays(GL_TRIANGLES, 0, 6);
+			glCheck();
+		}
+
+		chunkProg.disable();
 	}
 
 	glBindFramebuffer(GL_FRAMEBUFFER, state_->offscreenFramebuffer);
@@ -514,28 +500,11 @@ void Renderer::draw(const RenderCamera &cam) {
 	{
 		blendProg.enable();
 		glActiveTexture(GL_TEXTURE0);
-		glBindTexture(GL_TEXTURE_2D, state_->offscreenTex);
+		glBindTexture(GL_TEXTURE_2D, state_->opacityTex);
 		glDrawArrays(GL_TRIANGLES, 0, 6);
 		glCheck();
 		blendProg.disable();
 	}
-
-	{
-		chunkShadowProg.enable();
-		glUniformMatrix3fv(chunkShadowProg.camera, 1, GL_TRUE, camMat.data());
-		glCheck();
-
-		glActiveTexture(GL_TEXTURE0);
-		for (auto [pos, shadow]: drawChunkShadows_) {
-			glUniform2f(chunkShadowProg.pos, pos.x, pos.y);
-			glBindTexture(GL_TEXTURE_2D, shadow.tex);
-			glDrawArrays(GL_TRIANGLES, 0, 6);
-			glCheck();
-		}
-
-		drawChunkShadows_.clear();
-		chunkShadowProg.disable();
-	}
 }
 
 void Renderer::uploadTileAtlas(const void *data, int width, int height) {

libcygnet/src/shaders.cc

@@ -43,35 +43,6 @@ const char *chunkFr = R"glsl(
 	}
 )glsl";
 
-const char *chunkShadowVx = R"glsl(
-	precision mediump float;
-	#define CHUNK_WIDTH 64
-	#define CHUNK_HEIGHT 64
-
-	uniform mat3 camera;
-	uniform vec2 pos;
-	attribute vec2 vertex;
-	varying vec2 v_texCoord;
-
-	void main() {
-		vec3 pos = camera * vec3(pos + vertex, 1);
-		gl_Position = vec4(pos.xy, 0, 1);
-		v_texCoord = vertex / vec2(CHUNK_WIDTH, CHUNK_HEIGHT);
-	}
-)glsl";
-
-const char *chunkShadowFr = R"glsl(
-	precision mediump float;
-
-	varying vec2 v_texCoord;
-	uniform sampler2D tex;
-
-	void main() {
-		vec4 color = texture2D(tex, v_texCoord);
-		gl_FragColor = vec4(0, 0, 0, 1.0 - color.r);
-	}
-)glsl";
-
 const char *tileVx = R"glsl(
 	precision mediump float;
 	uniform mat3 camera;