使用skybox做球体的反射

main.cpp

@@ -78,18 +78,31 @@ INT WINAPI WinMain(_In_ HINSTANCE hInstance, _In_opt_ HINSTANCE hPrevInstance, _
 	gpuProgram.AttachShader(GL_VERTEX_SHADER, "res/shader/skybox.vs");
 	gpuProgram.AttachShader(GL_FRAGMENT_SHADER, "res/shader/skybox.fs");
 	gpuProgram.Link();
-
 	gpuProgram.DetectAttribute("pos");
 	gpuProgram.DetectAttribute("texcoord");
 	gpuProgram.DetectAttribute("normal");
 	gpuProgram.DetectUniform("M");
 	gpuProgram.DetectUniform("V");
 	gpuProgram.DetectUniform("P");
-	
+
+	//reflect program
+	GPUProgram reflectProgram;
+	reflectProgram.AttachShader(GL_VERTEX_SHADER, "res/shader/skybox_reflect.vs");
+	reflectProgram.AttachShader(GL_FRAGMENT_SHADER, "res/shader/skybox_reflect.fs");
+	reflectProgram.Link();
+	reflectProgram.DetectAttribute("pos");
+	reflectProgram.DetectAttribute("texcoord");
+	reflectProgram.DetectAttribute("normal");
+	reflectProgram.DetectUniform("M");
+	reflectProgram.DetectUniform("V");
+	reflectProgram.DetectUniform("P");
+	reflectProgram.DetectUniform("NM");
+	reflectProgram.DetectUniform("U_MainTexture");
 
 	//init 3d model
-	ObjModel cube;
-	cube.Init("res/model/Sphere.obj");
+	ObjModel cube,sphere;
+	cube.Init("res/model/Cube.obj");
+	sphere.Init("res/model/Sphere.obj");
 
 	float identity[] = {
 		1.0f,0,0,0,
@@ -102,6 +115,9 @@ INT WINAPI WinMain(_In_ HINSTANCE hInstance, _In_opt_ HINSTANCE hPrevInstance, _
 	glm::mat4 cubeModelMatrix;
 	glm::mat4 projectionMatrix = glm::perspective(50.0f, (float)viewportWidth / (float)viewportHeight, 0.1f, 1000.0f);
 
+	glm::mat4 sphereModelMatrix = glm::translate(0.0f, 0.0f, -4.0f);
+	glm::mat4 sphereNormalMatrix = glm::inverseTranspose(sphereModelMatrix);
+
 	GLuint mainTexture = SOIL_load_OGL_cubemap(
 		"res/image/right.bmp",
 		"res/image/left.bmp",
@@ -141,6 +157,18 @@ INT WINAPI WinMain(_In_ HINSTANCE hInstance, _In_opt_ HINSTANCE hPrevInstance, _
 		cube.Draw();
 		glUseProgram(0);
 		glEnable(GL_DEPTH_TEST);
+
+		glUseProgram(reflectProgram.mProgram);
+		glUniformMatrix4fv(reflectProgram.GetLocation("V"), 1, GL_FALSE, identity);
+		glUniformMatrix4fv(reflectProgram.GetLocation("P"), 1, GL_FALSE, glm::value_ptr(projectionMatrix));
+		glUniformMatrix4fv(reflectProgram.GetLocation("M"), 1, GL_FALSE, glm::value_ptr(sphereModelMatrix));
+		glUniformMatrix4fv(reflectProgram.GetLocation("NM"), 1, GL_FALSE, glm::value_ptr(sphereNormalMatrix));
+		glBindTexture(GL_TEXTURE_CUBE_MAP, mainTexture);
+		glUniform1i(reflectProgram.GetLocation("U_MainTexture"), 0);
+		sphere.Bind(reflectProgram.GetLocation("pos"), reflectProgram.GetLocation("texcoord"), reflectProgram.GetLocation("normal"));
+		sphere.Draw();
+		glUseProgram(0);
+
 		glFlush();
 		SwapBuffers(dc);
 	}

res/shader/skybox_reflect.fs

@@ -0,0 +1,13 @@
+
+varying vec4 V_WorldPos;
+varying vec3 V_Normal;
+
+uniform samplerCube U_MainTexture;
+
+void main()
+{
+	vec3 eyeVec = normalize(V_WorldPos.xyz - vec3(0.0));
+	vec3 n = normalize(V_Normal);
+	vec3 r = reflect(eyeVec, n);
+	gl_FragColor=textureCube(U_MainTexture, r);
+}

res/shader/skybox_reflect.vs

@@ -0,0 +1,18 @@
+attribute vec3 pos;
+attribute vec2 texcoord;
+attribute vec3 normal;
+
+uniform mat4 M;
+uniform mat4 P;
+uniform mat4 V;
+uniform mat4 NM;
+
+varying vec4 V_WorldPos;
+varying vec3 V_Normal;
+
+void main()
+{
+	V_WorldPos = M * vec4(pos,1.0);
+	V_Normal = mat3(NM)*normal;
+	gl_Position = P * V * V_WorldPos;
+}

shader3.vcxproj

@@ -82,8 +82,8 @@
     <ClInclude Include="utils.h" />
   </ItemGroup>
   <ItemGroup>
-    <None Include="res\shader\skybox.fs" />
-    <None Include="res\shader\skybox.vs" />
+    <None Include="res\shader\skybox_reflect.fs" />
+    <None Include="res\shader\skybox_reflect.vs" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">

shader3.vcxproj.filters

@@ -46,10 +46,10 @@
     </ClInclude>
   </ItemGroup>
   <ItemGroup>
-    <None Include="res\shader\skybox.fs">
+    <None Include="res\shader\skybox_reflect.fs">
       <Filter>src</Filter>
     </None>
-    <None Include="res\shader\skybox.vs">
+    <None Include="res\shader\skybox_reflect.vs">
       <Filter>src</Filter>
     </None>
   </ItemGroup>