正交投影视锥体

frustum.cpp

@@ -54,6 +54,32 @@ void Frustum::InitPerspective(float fov, float aspect, float zNear, float zFar)
 
 }
 
+void Frustum::InitOrtho(float left, float right, float bottom, float top, float zNear, float zFar)
+{
+
+
+	float vertexes[24] = {
+		left,bottom,-zNear,
+		right,bottom,-zNear,
+		right,top,-zNear,
+		left,top,-zNear,
+
+		left,bottom,-zFar,
+		right,bottom,-zFar,
+		right,top,-zFar,
+		left,top,-zFar,
+	};
+
+	mVBO = CreateBufferObject(GL_ARRAY_BUFFER, sizeof(float) * 24, GL_STATIC_DRAW, vertexes);
+
+	unsigned int indexes[] = {
+		0,1,1,2,2,3,3,0, //½ü¼ô²ÃÃæ
+		4,5,5,6,6,7,7,4, //Ô¶¼ô²ÃÃæ
+		0,4,3,7,2,6,1,5
+	};
+	mIBO = CreateBufferObject(GL_ELEMENT_ARRAY_BUFFER, sizeof(int) * 24, GL_STATIC_DRAW, indexes);
+}
+
 void Frustum::Draw(float* M, float* V, float* P)
 {
 	glUseProgram(mProgram);

frustum.h

@@ -10,5 +10,6 @@ public:
 	Frustum();
 	void Init();
 	void InitPerspective(float fov, float aspect, float zNear, float zFar);
+	void InitOrtho(float left, float right, float bottom, float top, float zNear, float zFar);
 	void Draw(float* M, float* V, float* P);
 };

main.cpp

@@ -133,6 +133,8 @@ INT WINAPI WinMain(HINSTANCE hinstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine
 	glEnable(GL_DEPTH_TEST);
 	glEnable(GL_POINT_SPRITE);
 	glEnable(GL_PROGRAM_POINT_SIZE);
+	glEnable(GL_BLEND);
+	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 	glViewport(0,0, windowWidth, windowHeight);
 
 	//创建一个单位矩阵和一个投影矩阵，后面用来传递到shader
@@ -143,13 +145,14 @@ INT WINAPI WinMain(HINSTANCE hinstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine
 		0,0,0,1
 	};
 
-	glm::mat4 model = glm::translate(-1.0f, 0.0f, -3.0f)*glm::rotate(-20.0f, 0.0f, 1.0f, 0.0f);
+	glm::mat4 model = glm::translate(0.0f, 0.0f, -3.0f)*glm::rotate(-20.0f, 0.0f, 1.0f, 0.0f);
 	glm::mat4 projection = glm::perspective(45.0f, (float)windowWidth / (float)windowHeight, 0.1f, 1000.0f);
 	glm::mat4 normalMatrix = glm::inverseTranspose(model);
 
 	Frustum frustum;
 	frustum.Init();
-	frustum.InitPerspective(45.0f, (float)windowWidth / (float)windowHeight, 0.1f, 4.0f);
+	//frustum.InitPerspective(45.0f, (float)windowWidth / (float)windowHeight, 0.1f, 4.0f);
+	frustum.InitOrtho(-0.5f, 0.5f,-0.5, 0.5,0.1f,4.0f);
 
 	/*显示窗口*/
 	ShowWindow(hwnd, SW_SHOW);