【OpenGL】丢弃片段——消融案例
作者：互联网
// ADS Point lighting Shader
// Vertex Shader
// Richard S. Wright Jr.
// OpenGL SuperBible
#version 130
// Incoming per vertex... position and normal
in vec4 vVertex;
in vec3 vNormal;
in vec2 vTexCoords0;
uniform mat4 mvpMatrix;
uniform mat4 mvMatrix;
uniform mat3 normalMatrix;
uniform vec3 vLightPosition;
// Color to fragment program
smooth out vec3 vVaryingNormal;
smooth out vec3 vVaryingLightDir;
smooth out vec2 vVaryingTexCoord;
void main(void)
{
// Pass on the texture coordinates
vVaryingTexCoord = vTexCoords0;
// Get surface normal in eye coordinates
vVaryingNormal = normalMatrix * vNormal;
// Get vertex position in eye coordinates
vec4 vPosition4 = mvMatrix * vVertex;
vec3 vPosition3 = vPosition4.xyz / vPosition4.w;
// Get vector to light source
vVaryingLightDir = normalize(vLightPosition - vPosition3);
// Don't forget to transform the geometry!
gl_Position = mvpMatrix * vVertex;
}
// ADS Point lighting Shader
// Fragment Shader
// Richard S. Wright Jr.
// OpenGL SuperBible
#version 130
out vec4 vFragColor;
uniform vec4 ambientColor;
uniform vec4 diffuseColor;
uniform vec4 specularColor;
uniform sampler2D cloudTexture;
uniform float dissolveFactor;
smooth in vec3 vVaryingNormal;
smooth in vec3 vVaryingLightDir;
smooth in vec2 vVaryingTexCoord;
void main(void)
{
vec4 vCloudSample = texture(cloudTexture, vVaryingTexCoord);
if(vCloudSample.r < dissolveFactor)
discard;
// Dot product gives us diffuse intensity
float diff = max(0.0, dot(normalize(vVaryingNormal), normalize(vVaryingLightDir)));
// Multiply intensity by diffuse color, force alpha to 1.0
vFragColor = diff * diffuseColor;
// Add in ambient light
vFragColor += ambientColor;
// Specular Light
vec3 vReflection = normalize(reflect(-normalize(vVaryingLightDir), normalize(vVaryingNormal)));
float spec = max(0.0, dot(normalize(vVaryingNormal), vReflection));
if(diff != 0) {
float fSpec = pow(spec, 128.0);
vFragColor.rgb += vec3(fSpec, fSpec, fSpec);
}
}
// Dissolve.cpp
// OpenGL SuperBible
// Demonstrates discard fragment command
// Program by Richard S. Wright Jr.
#pragma comment(lib, "gltools.lib")
#include <GLTools.h> // OpenGL toolkit
#include <GLMatrixStack.h>
#include <GLFrame.h>
#include <GLFrustum.h>
#include <GLGeometryTransform.h>
#include <StopWatch.h>
#include <math.h>
#ifdef __APPLE__
#include <glut/glut.h>
#else
#define FREEGLUT_STATIC
#include <GL/glut.h>
#endif
GLFrame viewFrame;
GLFrustum viewFrustum;
GLTriangleBatch torusBatch;
GLMatrixStack modelViewMatrix;
GLMatrixStack projectionMatrix;
GLGeometryTransform transformPipeline;
GLShaderManager shaderManager;
GLuint ADSDissloveShader; // The dissolving light shader
GLint locAmbient; // The location of the ambient color
GLint locDiffuse; // The location of the diffuse color
GLint locSpecular; // The location of the specular color
GLint locLight; // The location of the Light in eye coordinates
GLint locMVP; // The location of the ModelViewProjection matrix uniform
GLint locMV; // The location of the ModelView matrix uniform
GLint locNM; // The location of the Normal matrix uniform
GLint locTexture; // The location of the texture uniform
GLint locDissolveFactor; // The location of the dissolve factor
GLuint cloudTexture; // The cloud texture texture object
// Load a TGA as a 2D Texture. Completely initialize the state
bool LoadTGATexture(const char *szFileName, GLenum minFilter, GLenum magFilter, GLenum wrapMode)
{
GLbyte *pBits;
int nWidth, nHeight, nComponents;
GLenum eFormat;
// Read the texture bits
pBits = gltReadTGABits(szFileName, &nWidth, &nHeight, &nComponents, &eFormat);
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, nComponents, nWidth, nHeight, 0,
eFormat, 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;
}
// This function does any needed initialization on the rendering
// context.
void SetupRC(void)
{
// Background
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
glEnable(GL_DEPTH_TEST);
shaderManager.InitializeStockShaders();
viewFrame.MoveForward(4.0f);
// Make the torus
gltMakeTorus(torusBatch, .80f, 0.25f, 52, 26);
ADSDissloveShader = gltLoadShaderPairWithAttributes("Dissolve.vp", "Dissolve.fp", 3, GLT_ATTRIBUTE_VERTEX, "vVertex",
GLT_ATTRIBUTE_NORMAL, "vNormal", GLT_ATTRIBUTE_TEXTURE0, "vTexCoords0");
locAmbient = glGetUniformLocation(ADSDissloveShader, "ambientColor");
locDiffuse = glGetUniformLocation(ADSDissloveShader, "diffuseColor");
locSpecular = glGetUniformLocation(ADSDissloveShader, "specularColor");
locLight = glGetUniformLocation(ADSDissloveShader, "vLightPosition");
locMVP = glGetUniformLocation(ADSDissloveShader, "mvpMatrix");
locMV = glGetUniformLocation(ADSDissloveShader, "mvMatrix");
locNM = glGetUniformLocation(ADSDissloveShader, "normalMatrix");
locTexture = glGetUniformLocation(ADSDissloveShader, "cloudTexture");
locDissolveFactor = glGetUniformLocation(ADSDissloveShader, "dissolveFactor");
glGenTextures(1, &cloudTexture);
glBindTexture(GL_TEXTURE_2D, cloudTexture);
LoadTGATexture("Clouds.tga", GL_LINEAR_MIPMAP_LINEAR, GL_LINEAR, GL_CLAMP_TO_EDGE);
}
// Cleanup
void ShutdownRC(void)
{
glDeleteTextures(1, &cloudTexture);
}
// Called to draw scene
void RenderScene(void)
{
static CStopWatch rotTimer;
// Clear the window and the depth buffer
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
modelViewMatrix.PushMatrix(viewFrame);
modelViewMatrix.Rotate(rotTimer.GetElapsedSeconds() * 10.0f, 0.0f, 1.0f, 0.0f);
GLfloat vEyeLight[] = { -100.0f, 100.0f, 100.0f };
GLfloat vAmbientColor[] = { 0.1f, 0.1f, 0.1f, 1.0f };
GLfloat vDiffuseColor[] = { 0.1f, 1.0f, 0.1f, 1.0f };
GLfloat vSpecularColor[] = { 1.0f, 1.0f, 1.0f, 1.0f };
glUseProgram(ADSDissloveShader);
glUniform4fv(locAmbient, 1, vAmbientColor);
glUniform4fv(locDiffuse, 1, vDiffuseColor);
glUniform4fv(locSpecular, 1, vSpecularColor);
glUniform3fv(locLight, 1, vEyeLight);
glUniformMatrix4fv(locMVP, 1, GL_FALSE, transformPipeline.GetModelViewProjectionMatrix());
glUniformMatrix4fv(locMV, 1, GL_FALSE, transformPipeline.GetModelViewMatrix());
glUniformMatrix3fv(locNM, 1, GL_FALSE, transformPipeline.GetNormalMatrix());
glUniform1i(locTexture, 0); //glUniform1i(locTexture, 1); 草 源码尼玛用了1，实际只有0
float fFactor = fmod(rotTimer.GetElapsedSeconds(), 10.0f);
fFactor /= 10.0f;
glUniform1f(locDissolveFactor, fFactor);
torusBatch.Draw();
modelViewMatrix.PopMatrix();
glutSwapBuffers();
glutPostRedisplay();
}
void ChangeSize(int w, int h)
{
// Prevent a divide by zero
if (h == 0)
h = 1;
// Set Viewport to window dimensions
glViewport(0, 0, w, h);
viewFrustum.SetPerspective(35.0f, float(w) / float(h), 1.0f, 100.0f);
projectionMatrix.LoadMatrix(viewFrustum.GetProjectionMatrix());
transformPipeline.SetMatrixStacks(modelViewMatrix, projectionMatrix);
}
///
// Main entry point for GLUT based programs
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("Help me, I'm melting!");
glutReshapeFunc(ChangeSize);
glutDisplayFunc(RenderScene);
GLenum err = glewInit();
if (GLEW_OK != err) {
fprintf(stderr, "GLEW Error: %s\n", glewGetErrorString(err));
return 1;
}
SetupRC();
glutMainLoop();
ShutdownRC();
return 0;
}
标签：片段,ADSDissloveShader,1.0,OpenGL,void,TEXTURE,uniform,消融,GL 来源： https://blog.csdn.net/qq_39574690/article/details/115442152