渲染fbo到多个纹理

main.cpp

@@ -91,7 +91,7 @@ INT WINAPI WinMain(HINSTANCE hinstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine
 	glewInit();
 
 	/*´´½¨program*/
-	GLuint program = CreateGPUProgram("res/shader/test.vs", "res/shader/test.fs");
+	GLuint program = CreateGPUProgram("res/shader/MixLightMT.vs", "res/shader/MixLightMT.fs");
 
 	GLuint posLocation, texcoordLocation, normalLocation, MLocation, VLocation, PLocation, NMLocation, textureLocation, offsetLocation;
 	posLocation = glGetAttribLocation(program, "pos");
@@ -134,8 +134,8 @@ INT WINAPI WinMain(HINSTANCE hinstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine
 	GLuint mainTexture = CreateTextureFromFile("res/image/niutou.bmp");
 
 	/*´´½¨FBO*/
-	GLuint colorBuffer, depthBuffer;
-	GLuint fbo = CreateFramebufferObject(colorBuffer, depthBuffer, windowWidth, windowHeight);
+	GLuint colorBuffer, depthBuffer, colorBuffer2;
+	GLuint fbo = CreateFramebufferObject(colorBuffer, depthBuffer, windowWidth, windowHeight, &colorBuffer2);
 
 	glViewport(0, 0, windowWidth, windowHeight);
 
@@ -208,15 +208,27 @@ INT WINAPI WinMain(HINSTANCE hinstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine
 		GL_CALL(glClearColor(0.5f, 0.4f, 0.7f, 1.0f));
 		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 		glEnable(GL_TEXTURE_2D);
-		glBindTexture(GL_TEXTURE_2D, colorBuffer);
+		glEnable(GL_SCISSOR_TEST);
 
+		glBindTexture(GL_TEXTURE_2D, colorBuffer);
+		glScissor(0, 0, windowWidth, windowHeight/2);
 		glBegin(GL_QUADS);
-		glTexCoord2f(0.0f, 0.0f); glVertex3f(-0.5f, -0.5f, -4.0f);
-		glTexCoord2f(1.0f, 0.0f); glVertex3f(0.5f, -0.5f, -4.0f);
-		glTexCoord2f(1.0f, 1.0f); glVertex3f(0.5f, 0.5f, -4.0f);
-		glTexCoord2f(0.0f, 1.0f); glVertex3f(-0.5f, 0.5f, -4.0f);
+		glTexCoord2f(0.0f, 0.0f); glVertex3f(-0.5f, -0.5f, -1.0f);
+		glTexCoord2f(1.0f, 0.0f); glVertex3f(0.5f, -0.5f, -1.0f);
+		glTexCoord2f(1.0f, 1.0f); glVertex3f(0.5f, 0.5f, -1.0f);
+		glTexCoord2f(0.0f, 1.0f); glVertex3f(-0.5f, 0.5f, -1.0f);
 		glEnd();
 
+		glBindTexture(GL_TEXTURE_2D, colorBuffer2);
+		glScissor(0, windowHeight / 2, windowWidth, windowHeight / 2);
+		glBegin(GL_QUADS);
+		glTexCoord2f(0.0f, 0.0f); glVertex3f(-0.5f, -0.5f, -1.0f);
+		glTexCoord2f(1.0f, 0.0f); glVertex3f(0.5f, -0.5f, -1.0f);
+		glTexCoord2f(1.0f, 1.0f); glVertex3f(0.5f, 0.5f, -1.0f);
+		glTexCoord2f(0.0f, 1.0f); glVertex3f(-0.5f, 0.5f, -1.0f);
+		glEnd();
+		
+		glDisable(GL_SCISSOR_TEST);
 		SwapBuffers(dc);
 	}
 

misc.cpp

@@ -26,7 +26,7 @@ GLuint CreateVAOWithVBOSettings(std::function<void()> settings)
 	return vao;
 }
 
-GLuint CreateFramebufferObject(GLuint & colorBuffer, GLuint & depthBuffer, int width, int height)
+GLuint CreateFramebufferObject(GLuint & colorBuffer, GLuint & depthBuffer, int width, int height, GLuint *colorBuffer2)
 {
 	GLuint fbo;
 	glGenFramebuffers(1, &fbo);
@@ -43,6 +43,21 @@ GLuint CreateFramebufferObject(GLuint & colorBuffer, GLuint & depthBuffer, int w
 	glBindTexture(GL_TEXTURE_2D, 0);
 	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, colorBuffer, 0);//绑定刚才生成的texture到GL_COLOR_ATTACHMENT0
 
+	//colorbuffer2
+	if (colorBuffer2 != nullptr) {
+		glGenTextures(1, colorBuffer2);
+		glBindTexture(GL_TEXTURE_2D, *colorBuffer2);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
+		glBindTexture(GL_TEXTURE_2D, 0);
+		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_2D, *colorBuffer2, 0);//绑定刚才生成的texture到GL_COLOR_ATTACHMENT0
+		GLenum buffers[] = { GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1 };
+		glDrawBuffers(2, buffers);
+	}
+
 	//depthbuffer
 	glGenTextures(1, &depthBuffer);
 	glBindTexture(GL_TEXTURE_2D, depthBuffer);

misc.h

@@ -4,7 +4,7 @@
 
 GLuint CreateBufferObject(GLenum bufferType, GLsizeiptr size, GLenum usage, void* data = nullptr);
 GLuint CreateVAOWithVBOSettings(std::function<void()>settings);
-GLuint CreateFramebufferObject(GLuint &colorBuffer, GLuint &depthBuffer, int width, int height);
+GLuint CreateFramebufferObject(GLuint &colorBuffer, GLuint &depthBuffer, int width, int height, GLuint *colorBuffer2 = nullptr);
 
 char* LoadFileContent(const char *path);
 GLuint CompileShader(GLenum shaderType, const char* shaderPath);

res/shader/MixLightMT.fs

@@ -0,0 +1,35 @@
+uniform sampler2D U_MainTexture;
+varying vec3 V_Normal;
+varying vec4 V_WorldPos;//当前的位置
+varying vec2 V_Texcoord;
+
+void main() {
+
+	vec3 lightPos = vec3(10.0, 10.0, 0.0);
+	vec3 L=lightPos;
+	L = normalize(L);
+	vec3 n = normalize(V_Normal);
+
+
+	//ambient
+	vec4 AmbientLightColor = vec4(0.2, 0.2, 0.2, 1.0);
+	vec4 AmbientMaterial = vec4(0.2, 0.2, 0.2, 1.0);
+	vec4 AmbientColor = AmbientLightColor*AmbientMaterial;
+
+	//diffuse
+	vec4 DiffuseLightColor = vec4(1.0,1.0,1.0,1.0);
+	vec4 DiffuseMaterial = vec4(0.8, 0.8, 0.8, 1.0);
+	vec4 diffuseColor = DiffuseLightColor*DiffuseMaterial*max(0.0, dot(L,n));
+
+	//specular
+	vec4 SpecularLightColor = vec4(1.0,1.0,1.0,1.0);
+	vec4 SpecularMaterial = vec4(0.9,0.9,0.9,1.0);
+	vec3 reflectDir = normalize(reflect(-L,n));//-L就是光线的入射方向向量，以法线为基础计算方式向量
+	vec3 viewDir = normalize(vec3(0.0) - V_WorldPos.xyz);//vec3(0.0)表示已中心为观察点，这里求的是眼睛到物体的视线向量
+	vec4 specularColor = SpecularLightColor*SpecularMaterial*pow(max(0.0,dot(viewDir,reflectDir)),128.0);
+
+
+	//gl_FragColor = texture2D(U_MainTexture, V_Texcoord) * (AmbientColor + diffuseColor + specularColor);
+	gl_FragData[0] = AmbientColor + texture2D(U_MainTexture, V_Texcoord) * diffuseColor + specularColor;
+	gl_FragData[1] = vec4(1.0);
+}

res/shader/MixLightMT.vs

@@ -0,0 +1,19 @@
+attribute vec3 pos;
+attribute vec2 texcoord;
+attribute vec3 normal;
+
+uniform mat4 M;
+uniform mat4 V;
+uniform mat4 P;
+uniform mat4 NM;
+
+varying vec3 V_Normal;
+varying vec4 V_WorldPos;//µ±Ç°µÄλÖÃ
+varying vec2 V_Texcoord;
+
+void main() {
+	V_Normal = mat3(NM)*normal;
+	V_WorldPos = M * vec4(pos, 1.0);
+	V_Texcoord = texcoord;
+	gl_Position = P*V*M*vec4(pos,1.0);	
+}

shader2.vcxproj

@@ -159,8 +159,8 @@
     <ClInclude Include="timer.h" />
   </ItemGroup>
   <ItemGroup>
-    <None Include="res\shader\MixLight.fs" />
-    <None Include="res\shader\MixLight.vs" />
+    <None Include="res\shader\MixLightMT.fs" />
+    <None Include="res\shader\MixLightMT.vs" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">

shader2.vcxproj.filters

@@ -46,10 +46,10 @@
     </ClInclude>
   </ItemGroup>
   <ItemGroup>
-    <None Include="res\shader\MixLight.fs">
+    <None Include="res\shader\MixLightMT.fs">
       <Filter>源文件</Filter>
     </None>
-    <None Include="res\shader\MixLight.vs">
+    <None Include="res\shader\MixLightMT.vs">
       <Filter>源文件</Filter>
     </None>
   </ItemGroup>