我的代码中有一个非常奇怪的问题，添加了名为“coord”的vec2用于包含我的纹理坐标，这些应该被传递到我的顶点着色器，传递到几何着色器，最后传递到片段着色器它将用于纹理映射。但由于某些原因，GLSL编译器正在优化掉vec2输入，使用glVertexAttribPointer分配给它没有结果，并用glGetUniformLocation(gShaderProgram, "coord");双重检查其位置返回-1，这表明它已被GLSL编译器优化，为什么？据我所知，编译器只会优化对着色器输出没有贡献的值，但会在每个着色器阶段中用作输出。这是一项单一的任务，所以这对我来说几乎都是新手。
顶点着色器
#version 440
layout(location = 0) in vec3 vertex_position;
layout(location = 1) in vec3 vertex_color;
layout(location = 2) in vec2 coord;
layout(location = 20) uniform vec4 test;
layout(binding = 3, std140) uniform uniformBlock
{
float v1;
float v2;
float v3;
float v4;
};
uniform mat4 m;
uniform mat4 p;
uniform mat4 v;
out vData
{
mat4 m;
mat4 p;
mat4 v;
vec4 test;
vec4 color;
vec2 tex_coord;
}vertices;
void main() {
vertices.m = m;
vertices.p = p;
vertices.v = v;
vertices.test = test;
vertices.tex_coord = coord;
vertices.color = vec4(vertex_color, 1.0);
gl_Position = vec4(vertex_position, 1.0);
}
几何着色器
#version 400
layout (triangles) in;
layout (triangle_strip, max_vertices = 6) out;
in vData
{
mat4 m;
mat4 p;
mat4 v;
vec4 test;
vec4 color;
vec2 tex_coord;
} vertices[];
out fData
{
vec3 normal;
vec4 color;
mat4 v;
vec2 tex_coord;
} frag;
void main()
{
vec3 A = gl_in[2].gl_Position.xyz - gl_in[0].gl_Position.xyz;
vec3 B = gl_in[1].gl_Position.xyz - gl_in[0].gl_Position.xyz;
vec3 normal = normalize(cross(A,B));
int i;
for(i = 0;i < gl_in.length();i++)
{
gl_Position = (vertices[i].p * vertices[i].v * vertices[i].m) * gl_in[i].gl_Position;
frag.normal = normalize(vec3(vertices[i].m * vec4(normal,0)));
frag.color = vertices[i].color;
frag.v = vertices[i].v;
frag.tex_coord = vertices[i].tex_coord;
EmitVertex();
}
EndPrimitive();
for(i = 0;i < gl_in.length();i++)
{
gl_Position = vertices[i].p * vertices[i].v * vertices[i].m * (gl_in[i].gl_Position + vec4(normal,0));
frag.normal = normalize(vec3(vertices[i].m * vec4(normal,0)));
frag.color = vertices[i].color;
frag.v = vertices[i].v;
frag.tex_coord = vertices[i].tex_coord;
EmitVertex();
}
EndPrimitive();
}
片段着色器
#version 400
out vec4 fragment_color;
const float PI = 3.14159265;
uniform sampler2D texture0;
in fData
{
vec3 normal;
vec4 color;
mat4 v;
vec2 tex_coord;
} frag;
void main () {
vec3 n = normalize(frag.normal);
float intensity = min(max(dot(n, vec3(0,0,-1)), 0.0), 1.0);
//fragment_color = frag.color * intensity * frag.tex_coord.s;
fragment_color = texture2D(texture0, frag.tex_coord.st);
}
main.cpp中
#include <vector>
#include <windows.h>
#include <iostream>
#include <string>
#include <fstream>
#include <streambuf>
#include <chrono>
#include <gl/glew.h>
#include <gl/GL.h>
# define M_PI 3.14159265358979323846
#include "glm\glm.hpp"
#include "glm\gtc\matrix_transform.hpp"
#include "bth_image.h"
#pragma comment(lib, "opengl32.lib")
#pragma comment(lib, "glew32.lib")
using namespace std;
using namespace glm;
HWND InitWindow(HINSTANCE hInstance);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
HGLRC CreateOpenGLContext(HWND wndHandle);
GLuint gVertexBuffer = 0;
GLuint gVertexAttribute = 0;
GLuint gShaderProgram = 0;
GLuint textures[1];
mat4x4 view;
mat4x4 world;
mat4x4 projection;
float DT;
struct CPUvalues
{
float v1;
float v2;
float v3;
float v4;
};
CPUvalues Gv = { 0.5, 0, 0, 0 };
GLuint gu = 0;
#define BUFFER_OFFSET(i) ((char *)nullptr + (i))
void CreateShaders()
{
GLuint vs = glCreateShader(GL_VERTEX_SHADER);
ifstream shaderFile("VertexShader.glsl");
std::string shaderText((std::istreambuf_iterator<char>(shaderFile)), std::istreambuf_iterator<char>());
shaderFile.close();
const char* shaderTextPtr = shaderText.c_str();
glShaderSource(vs, 1, &shaderTextPtr, nullptr);
glCompileShader(vs);
//create fragment shader | same process.
GLuint fs = glCreateShader(GL_FRAGMENT_SHADER);
shaderFile.open("Fragment.glsl");
shaderText.assign((std::istreambuf_iterator<char>(shaderFile)), std::istreambuf_iterator<char>());
shaderFile.close();
shaderTextPtr = shaderText.c_str();
glShaderSource(fs, 1, &shaderTextPtr, nullptr);
glCompileShader(fs);
GLuint gs = glCreateShader(GL_GEOMETRY_SHADER);
shaderFile.open("GMshader.glsl");
shaderText.assign((std::istreambuf_iterator<char>(shaderFile)), std::istreambuf_iterator<char>());
shaderFile.close();
shaderTextPtr = shaderText.c_str();
glShaderSource(gs, 1, &shaderTextPtr, nullptr);
glCompileShader(gs);
GLint success = 0;
glGetShaderiv(gs, GL_COMPILE_STATUS, &success);
if (success == GL_FALSE)
{
GLint logSize = 0;
glGetShaderiv(gs, GL_INFO_LOG_LENGTH, &logSize);
std::vector<GLchar> errorLog(logSize);
glGetShaderInfoLog(gs, logSize, &logSize, &errorLog[0]);
for (int i = 0; i < errorLog.size(); i++)
{
cout << errorLog.at(i);
}
}
//link shader program (connect vs and ps)
gShaderProgram = glCreateProgram();
glAttachShader(gShaderProgram, fs);
glAttachShader(gShaderProgram, gs);
glAttachShader(gShaderProgram, vs);
glBindAttribLocation(gShaderProgram, 1, "vertices");
glEnable(GL_TEXTURE_2D);
glGenTextures(1, textures);
glBindTexture(GL_TEXTURE_2D, textures[0]);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, BTH_IMAGE_WIDTH, BTH_IMAGE_HEIGHT, 0, GL_RGBA, GL_UNSIGNED_BYTE, (GLvoid*)BTH_IMAGE_DATA);
glLinkProgram(gShaderProgram);
GLint isLinked = 0;
glGetProgramiv(gShaderProgram, GL_LINK_STATUS, &isLinked);
if (isLinked == GL_FALSE)
{
GLint maxLength = 0;
glGetProgramiv(gShaderProgram, GL_INFO_LOG_LENGTH, &maxLength);
std::vector<GLchar> infoLog(maxLength);
glGetProgramInfoLog(gShaderProgram, maxLength, &maxLength, &infoLog[0]);
for (GLint i = 0; i < maxLength; i++)
{
cout << infoLog.at(i);
}
}
}
void CreateTriangleData()
{
// this is how we will structure the input data for the vertex shader
// every six floats, is one vertex.
struct TriangleVertex
{
float x, y, z;
float r, g, b;
float s, t;
};
// create the actual data in plane Z = 0
TriangleVertex triangleVertices[6] =
{
// pos and color for each vertex
{ -0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f },
{ 0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f },
{ -0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f },
{ 0.5f, 0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f },
{ 0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f },
{ -0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f }
};
// Vertex Array Object (VAO)
glGenVertexArrays(1, &gVertexAttribute);
// bind == enable
glBindVertexArray(gVertexAttribute);
// this activates the first and second attributes of this VAO
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
// create a vertex buffer object (VBO) id
glGenBuffers(1, &gVertexBuffer);
// Bind the buffer ID as an ARRAY_BUFFER
glBindBuffer(GL_ARRAY_BUFFER, gVertexBuffer);
// This "could" imply copying to the GPU, depending on what the driver wants to do...
glBufferData(GL_ARRAY_BUFFER, sizeof(triangleVertices), triangleVertices, GL_STATIC_DRAW);
// query where which slot corresponds to the input vertex_position in the Vertex Shader
GLint vertexPos = glGetAttribLocation(gShaderProgram, "vertex_position");
// specify that: the vertex attribute "vertexPos", of 3 elements of type FLOAT, not normalized, with STRIDE != 0,
// starts at offset 0 of the gVertexBuffer (it is implicitly bound!)
glVertexAttribPointer(vertexPos, 3, GL_FLOAT, GL_FALSE, sizeof(TriangleVertex), BUFFER_OFFSET(0));
// query where which slot corresponds to the input vertex_color in the Vertex Shader
GLint vertexColor = glGetAttribLocation(gShaderProgram, "vertex_color");
cout << "vertex pos " << vertexPos << endl;
cout << "vertex color " << vertexColor << endl;
// specify that: the vertex attribute "vertex_color", of 3 elements of type FLOAT, not normalized, with STRIDE != 0,
// starts at offset (12 bytes) of the gVertexBuffer
glVertexAttribPointer(vertexColor, 3, GL_FLOAT, GL_FALSE, sizeof(TriangleVertex), BUFFER_OFFSET(sizeof(float)*3));
cout << glGetError() << endl;
GLint tex_coord = glGetUniformLocation(gShaderProgram, "coord");
cout << "coord " << tex_coord << endl;
glVertexAttribPointer(tex_coord, 2, GL_FLOAT, GL_FALSE, sizeof(TriangleVertex), BUFFER_OFFSET(sizeof(float) * 6));
cout << glGetError() << endl;
}
void SetViewport()
{
glViewport(0, 0, 640, 480);
}
void Render()
{
// set the color TO BE used
glClearColor(0, 0, 0, 1);
// use the color to clear the color buffer
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glUseProgram(gShaderProgram);
glBindVertexArray(gVertexAttribute);
glGenBuffers(1, &gu);
glBindBuffer(GL_UNIFORM_BUFFER, gu);
glBufferSubData(GL_UNIFORM_BUFFER, 0, sizeof(CPUvalues), &Gv);
GLint OG_loc = glGetUniformLocation(gShaderProgram, "test");
GLint _p = glGetUniformLocation(gShaderProgram, "p");
GLint _m = glGetUniformLocation(gShaderProgram, "m");
GLint _v = glGetUniformLocation(gShaderProgram, "v");
GLuint unit = 0;
GLint texture0 = glGetUniformLocation(gShaderProgram, "texture0");
//cout << glGetUniformLocation(gShaderProgram, "coord") << endl;;
glActiveTexture(GL_TEXTURE0 + unit);
glBindTexture(GL_TEXTURE_2D, textures[0]);
glUniform1i(texture0, unit);
glUniformMatrix4fv(_p, 1, GL_FALSE, &projection[0][0]);
glUniformMatrix4fv(_m, 1, GL_FALSE, &world[0][0]);
glUniformMatrix4fv(_v, 1, GL_FALSE, &view[0][0]);
glUniform4f(OG_loc, Gv.v1, Gv.v2, Gv.v3, Gv.v4);
// draw 3 vertices starting from index 0 in the vertex array currently bound (VAO), with current in-use shader
glEnable(GL_DEPTH_TEST);
glEnable(GL_CULL_FACE);
glFrontFace(GL_CW);
glCullFace(GL_BACK);
glDrawArrays(GL_TRIANGLES, 0, 6);
}
int WINAPI wWinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPWSTR lpCmdLine, int nCmdShow )
{
AllocConsole();
freopen("CONOUT$", "w", stdout);
DT = 0.016;
MSG msg = { 0 };
HWND wndHandle = InitWindow(hInstance); //1. Skapa fönster
if (wndHandle)
{
HDC hDC = GetDC(wndHandle);
HGLRC hRC = CreateOpenGLContext(wndHandle); //2. Skapa och koppla OpenGL context
glewInit(); //3. Initiera The OpenGL Extension Wrangler Library (GLEW)
SetViewport(); //4. Sätt viewport
CreateShaders(); //5. Skapa vertex- och fragment-shaders
CreateTriangleData(); //6. Definiera triangelvertiser, 7. Skapa vertex buffer object (VBO), 8.Skapa vertex array object (VAO)
ShowWindow(wndHandle, nCmdShow);
view = lookAt(vec3(0, 0, -2), vec3(0, 0, 0), vec3(0, 1, 0));
mat4x4 sm;
sm = scale(sm, vec3(1, 1, 1));
mat4x4 tm;
tm = translate(tm, vec3(0, 0, 0));
mat4x4 rm;
rm = mat4x4(1);
projection = perspective<float>(M_PI*0.45, 640 / 480, 0.1, 20);
while (WM_QUIT != msg.message)
{
auto start_time = chrono::high_resolution_clock::now();
//Gv.v1 += 0.05 * DT;
Gv.v1 += 1 * DT;
world = tm * rotate(rm, Gv.v1, vec3(0, 1, 0)) * sm;
if (PeekMessage(&msg, nullptr, 0, 0, PM_REMOVE))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
else
{
Render(); //9. Rendera
SwapBuffers(hDC); //10. Växla front- och back-buffer
}
auto final_time = chrono::high_resolution_clock::now() - start_time;
DT = chrono::duration_cast<std::chrono::milliseconds>(final_time).count() / (double)1000;
}
wglMakeCurrent(NULL, NULL);
ReleaseDC(wndHandle, hDC);
wglDeleteContext(hRC);
DestroyWindow(wndHandle);
}
return (int) msg.wParam;
}
HWND InitWindow(HINSTANCE hInstance)
{
WNDCLASSEX wcex = { 0 };
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = WndProc;
wcex.hInstance = hInstance;
wcex.lpszClassName = L"BTH_GL_DEMO";
if( !RegisterClassEx(&wcex) )
return false;
RECT rc = { 0, 0, 640, 480 };
AdjustWindowRect( &rc, WS_OVERLAPPEDWINDOW, FALSE );
HWND handle = CreateWindow(
L"BTH_GL_DEMO",
L"BTH OpenGL Demo",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
rc.right - rc.left,
rc.bottom - rc.top,
nullptr,
nullptr,
hInstance,
nullptr);
return handle;
}
LRESULT CALLBACK WndProc( HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam )
{
switch (message)
{
case WM_DESTROY:
PostQuitMessage(0);
break;
}
return DefWindowProc(hWnd, message, wParam, lParam);
}
HGLRC CreateOpenGLContext(HWND wndHandle)
{
//get handle to a device context (DC) for the client area
//of a specified window or for the entire screen
HDC hDC = GetDC(wndHandle);
//details: http://msdn.microsoft.com/en-us/library/windows/desktop/dd318286(v=vs.85).aspx
static PIXELFORMATDESCRIPTOR pixelFormatDesc =
{
sizeof(PIXELFORMATDESCRIPTOR), // size of this pfd
1, // version number
PFD_DRAW_TO_WINDOW | // support window
PFD_SUPPORT_OPENGL | // support OpenGL
PFD_DOUBLEBUFFER, // double buffered
PFD_TYPE_RGBA, // RGBA type
32, // 32-bit color depth
0, 0, 0, 0, 0, 0, // color bits ignored
0, // no alpha buffer
0, // shift bit ignored
0, // no accumulation buffer
0, 0, 0, 0, // accum bits ignored
0, // 0-bits for depth buffer <-- modified by Stefan
0, // no stencil buffer
0, // no auxiliary buffer
PFD_MAIN_PLANE, // main layer
0, // reserved
0, 0, 0 // layer masks ignored
};
//attempt to match an appropriate pixel format supported by a
//device context to a given pixel format specification.
int pixelFormat = ChoosePixelFormat(hDC, &pixelFormatDesc);
//set the pixel format of the specified device context
//to the format specified by the iPixelFormat index.
SetPixelFormat(hDC, pixelFormat, &pixelFormatDesc);
//create a new OpenGL rendering context, which is suitable for drawing
//on the device referenced by hdc. The rendering context has the same
//pixel format as the device context.
HGLRC hRC = wglCreateContext(hDC);
//makes a specified OpenGL rendering context the calling thread's current
//rendering context. All subsequent OpenGL calls made by the thread are
//drawn on the device identified by hdc.
wglMakeCurrent(hDC, hRC);
return hRC;
}
您正尝试使用glGetUniformLocation查询属性位置。请改用glGetAttribLocation。