Texture mapping a pyramid

最新推荐文章于 2023-02-04 14:27:28 发布

原创最新推荐文章于 2023-02-04 14:27:28 发布 · 1.3k 阅读

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本文介绍了一个使用OpenGL进行金字塔渲染的示例程序。该程序通过GLSL着色器实现了带纹理的点光源光照效果，并允许用户通过键盘操作旋转金字塔。文章包含完整的源代码，适合初学者学习OpenGL基本渲染流程。

最近每晚都超累...脖子酸,脑袋昏沉...表示看书成问题...最近不知怎么了,特别特别累.

抄了一段书上的代码,跑了一遍.贴出来吧.

//	SphereWorld.cpp

#include "stdafx.h"
#include <GLTools.h>
#include <GLMatrixStack.h>
#include <GLFrame.h>
#include <GLFrustum.h>
#include <GLBatch.h>
#include <GLGeometryTransform.h>
#include <math.h>
#include <GL/glut.h>

GLShaderManager shaderManager ;
GLMatrixStack modelViewMatrix ;
GLMatrixStack projectionMatrix ;
GLFrame cameraFrame ;
GLFrame objectFrame ;
GLFrustum viewFrustum ;

GLBatch pyramidBatch ;
GLuint textureID ;

GLGeometryTransform transformPipeline ;
M3DMatrix44f shadowMatrix ;

void MakePyramid(GLBatch& pyramidBatch)
{
	pyramidBatch.Begin(GL_TRIANGLES, 18, 1);
    
	// Bottom of pyramid
	pyramidBatch.Normal3f(0.0f, -1.0f, 0.0f);
	pyramidBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
	pyramidBatch.Vertex3f(-1.0f, -1.0f, -1.0f);
    
	pyramidBatch.Normal3f(0.0f, -1.0f, 0.0f);
	pyramidBatch.MultiTexCoord2f(0, 1.0f, 0.0f);
	pyramidBatch.Vertex3f(1.0f, -1.0f, -1.0f);
    
	pyramidBatch.Normal3f(0.0f, -1.0f, 0.0f);
	pyramidBatch.MultiTexCoord2f(0, 1.0f, 1.0f);
	pyramidBatch.Vertex3f(1.0f, -1.0f, 1.0f);
    
	pyramidBatch.Normal3f(0.0f, -1.0f, 0.0f);
	pyramidBatch.MultiTexCoord2f(0, 0.0f, 1.0f);
	pyramidBatch.Vertex3f(-1.0f, -1.0f, 1.0f);
    
	pyramidBatch.Normal3f(0.0f, -1.0f, 0.0f);
	pyramidBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
	pyramidBatch.Vertex3f(-1.0f, -1.0f, -1.0f);
    
	pyramidBatch.Normal3f(0.0f, -1.0f, 0.0f);
	pyramidBatch.MultiTexCoord2f(0, 1.0f, 1.0f);
	pyramidBatch.Vertex3f(1.0f, -1.0f, 1.0f);
    
	
	M3DVector3f vApex = { 0.0f, 1.0f, 0.0f };
	M3DVector3f vFrontLeft = { -1.0f, -1.0f, 1.0f };
	M3DVector3f vFrontRight = { 1.0f, -1.0f, 1.0f };
	M3DVector3f vBackLeft = { -1.0f, -1.0f, -1.0f };
	M3DVector3f vBackRight = { 1.0f, -1.0f, -1.0f };
	M3DVector3f n;
	
	// Front of Pyramid
	m3dFindNormal(n, vApex, vFrontLeft, vFrontRight);
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 0.5f, 1.0f);
	pyramidBatch.Vertex3fv(vApex);		// Apex
    
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
	pyramidBatch.Vertex3fv(vFrontLeft);		// Front left corner
    
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 1.0f, 0.0f);
	pyramidBatch.Vertex3fv(vFrontRight);		// Front right corner
    
    
	m3dFindNormal(n, vApex, vBackLeft, vFrontLeft);
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 0.5f, 1.0f);
	pyramidBatch.Vertex3fv(vApex);		// Apex
    
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 1.0f, 0.0f);
	pyramidBatch.Vertex3fv(vBackLeft);		// Back left corner
	
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
	pyramidBatch.Vertex3fv(vFrontLeft);		// Front left corner
    
	m3dFindNormal(n, vApex, vFrontRight, vBackRight);
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 0.5f, 1.0f);
	pyramidBatch.Vertex3fv(vApex);				// Apex
    
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 1.0f, 0.0f);
	pyramidBatch.Vertex3fv(vFrontRight);		// Front right corner
    
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
	pyramidBatch.Vertex3fv(vBackRight);			// Back right cornder
    
    
	m3dFindNormal(n, vApex, vBackRight, vBackLeft);
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 0.5f, 1.0f);
	pyramidBatch.Vertex3fv(vApex);		// Apex
    
	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
	pyramidBatch.Vertex3fv(vBackRight);		// Back right cornder

	pyramidBatch.Normal3fv(n);
	pyramidBatch.MultiTexCoord2f(0, 1.0f, 0.0f);
	pyramidBatch.Vertex3fv(vBackLeft);		// Back left corner

	pyramidBatch.End();
}

bool LoadTGATexture(const char* szFileName, GLenum minFilter, GLenum magFilter, GLenum wrapMode)
{
	GLbyte * pBits ;
	int width, height, components ;
	GLenum format ;

	pBits = gltReadTGABits(szFileName, &width, &height, &components, &format) ;
	if (pBits == NULL)
		return false ;

	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, wrapMode) ;
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, wrapMode) ;
	
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, minFilter) ;
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, magFilter) ;

	glPixelStorei(GL_UNPACK_ALIGNMENT, 1) ;
	glTexImage2D(GL_TEXTURE_2D, 0, components, width, height, 0, format, GL_UNSIGNED_BYTE, pBits) ;

	free(pBits) ;

	if (minFilter == GL_LINEAR_MIPMAP_LINEAR ||
		minFilter == GL_LINEAR_MIPMAP_NEAREST ||
		minFilter == GL_NEAREST_MIPMAP_LINEAR ||
		minFilter== GL_NEAREST_MIPMAP_NEAREST)
	{
		glGenerateMipmap(GL_TEXTURE_2D) ;
	}

	return true ;
}

void SetUpRC()
{
	glClearColor(0.7f, 0.7f, 0.7f, 1.0f) ;

	shaderManager.InitializeStockShaders() ;

	glEnable(GL_DEPTH_TEST) ;

	glGenTextures(1, &textureID) ;
	glBindTexture(GL_TEXTURE_2D, textureID) ;
	LoadTGATexture("stone.tga", GL_LINEAR, GL_LINEAR, GL_CLAMP_TO_EDGE) ;

	MakePyramid(pyramidBatch) ;

	cameraFrame.MoveForward(-7.0f) ;
}

void ShutdownRC(void)
{
	glDeleteTextures(1, &textureID) ;
}

void RenderScene(void)
{
	static GLfloat lightPos[] = {1.0f,1.0f, 1.0f,} ;
	static GLfloat white[] = {1.0f, 1.0f, 1.0f, 1.0f,} ;

	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT) ;

	modelViewMatrix.PushMatrix() ;
	M3DMatrix44f mCamera ;
	cameraFrame.GetCameraMatrix(mCamera) ;
	modelViewMatrix.MultMatrix(mCamera) ;

	M3DMatrix44f mObjectFrame ;
	objectFrame.GetMatrix(mObjectFrame) ;
	modelViewMatrix.MultMatrix(mObjectFrame) ;

	glBindTexture(GL_TEXTURE_2D, textureID) ;
	shaderManager.UseStockShader(
		GLT_SHADER_TEXTURE_POINT_LIGHT_DIFF,
		transformPipeline.GetModelViewMatrix(),
		transformPipeline.GetProjectionMatrix(),
		lightPos, white, 0) ;

	pyramidBatch.Draw() ;

	modelViewMatrix.PopMatrix() ;

	glutSwapBuffers() ;
}

void SpecialKeys(int key, int x, int y)
{
	if (key == GLUT_KEY_UP)
		objectFrame.RotateWorld(m3dDegToRad(-5.0f), 1.0f, 0, 0) ;

	if (key == GLUT_KEY_DOWN)
		objectFrame.RotateWorld(m3dDegToRad(5.0f), 1.0f, 0, 0) ;

	if (key == GLUT_KEY_LEFT)
		objectFrame.RotateWorld(m3dDegToRad(-5.0f), 0, 1.0f, 0) ;

	if (key == GLUT_KEY_RIGHT)
		objectFrame.RotateWorld(m3dDegToRad(5.0f), 0, 1.0f, 0) ;

	glutPostRedisplay() ;
}

void ChangeSize(int w, int h)
{
	glViewport(0, 0, w, h) ;
	viewFrustum.SetPerspective(35.0f, (float)w / h, 1.0f, 500.0f) ;
	projectionMatrix.LoadMatrix(viewFrustum.GetProjectionMatrix()) ;
	transformPipeline.SetMatrixStacks(modelViewMatrix, projectionMatrix) ;
}

int main(int argc, char* argv[])
{
	gltSetWorkingDirectory(argv[0]);
	
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH | GLUT_STENCIL);
	glutInitWindowSize(800, 600);
	glutCreateWindow("Pyramid");
    glutReshapeFunc(ChangeSize);
    glutSpecialFunc(SpecialKeys);
    glutDisplayFunc(RenderScene);
        
	GLenum err = glewInit();

	if (GLEW_OK != err)
	{
		fprintf(stderr, "GLEW Error: %s\n", glewGetErrorString(err));
		return 1;
	}
	
	SetUpRC();

	glutMainLoop();
    
    ShutdownRC();
    
	return 0;
}