Xcode+Opengl學習（7）紋理設置

紋理基本設置
剛接觸紋理，很多函數不會用，定義也記不住，多用幾遍自然就好啦。

#include<GLTools.h>
#include<GLMatrixStack.h>
#include<GLFrame.h>
#include<GLFrustum.h>
#include<GLBatch.h>
#include<GLGeometryTransform.h>
#include<math.h>
#include<GLUT/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);

    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 nWidth, nHeight, nComponents;
    GLenum eFormat;

    pBits = gltReadTGABits(szFileName, &nWidth, &nHeight, &nComponents, &eFormat);

        //用來打開文件GLbyte *GltReadTGABits(const char *szFileName,GLint *iWidth,GLint *iHeight,GLint *iComponents,GLenum *eFormat)
    if(pBits==NULL)
        return false;
        //線形紋理和紋理環繞
    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);//指定opengl如何從數據緩衝區中解包圖像數據
                                        //.bmp文件格式的像素數據4個字節排列的，.tga文件格式是一個字節排列的
    glTexImage2D(GL_TEXTURE_2D,0,nComponents,nWidth,nHeight,0,eFormat,GL_UNSIGNED_BYTE,pBits);
        //載入紋理，void glTexImage2D(GLenum target,GLint level,GLint internalformat,GLsizei width,GLsizei height,GLint border,GLenum format,GLenum type,void *data)
    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("/Users/mac/Downloads/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 vLightPos [] = { 1.0f, 1.0f, 0.0f };
    static GLfloat vWhite [] = { 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_POINT_LIGHT_DIFF,transformPipeline.GetModelViewMatrix(),transformPipeline.GetProjectionMatrix());
    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, 0.0f, 0.0f);

    if(key == GLUT_KEY_DOWN)
        objectFrame.RotateWorld(m3dDegToRad(5.0f), 1.0f, 0.0f, 0.0f);

    if(key == GLUT_KEY_LEFT)
        objectFrame.RotateWorld(m3dDegToRad(-5.0f), 0.0f, 1.0f, 0.0f);

    if(key == GLUT_KEY_RIGHT)
        objectFrame.RotateWorld(m3dDegToRad(5.0f), 0.0f, 1.0f, 0.0f);

    glutPostRedisplay();
}

void ChangeSize(int w, int h)
{
    glViewport(0, 0, w, h);
    viewFrustum.SetPerspective(35.0f, float(w) / float(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;
}