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我想在OpenGL ES 2.x中使用C++和SDL 2渲染一個簡單的三角形。 但glCreateShader和glCreatProgram返回零。 貝婁是我使用glCreateShader和glCreateProgram返回0 SDL 2 IOS
#include "SDL.h"
#include <OpenGLES/ES2/gl.h>
#include <OpenGLES/ES2/glext.h>
#include <iostream>
#include <string>
#include <memory>
using namespace std;
GLuint programObject;
class Graphics
{
private:
SDL_Window* _window;
public:
Graphics(SDL_Window* window)
{
_window = window;
}
void update()
{
glClearColor(255.0f, 0.0f, 255.0f, 1);
// glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
GLfloat vVertices[] = {
0.0f, 0.5f, 0.0f,
-0.5f, -0.5f, 0.0f,
0.5f, -0.5f, 0.0f
};
glViewport (0, 0, 320, 480);
glColorMask (GL_TRUE, GL_TRUE, GL_TRUE, GL_FALSE);
glClear (GL_COLOR_BUFFER_BIT);
glUseProgram (programObject);
glVertexAttribPointer (0, 3, GL_FLOAT, GL_FALSE, 0, vVertices);
glEnableVertexAttribArray (0);
glDrawArrays (GL_TRIANGLES, 0, 3);
SDL_GL_SwapWindow(_window);
}
};
void UpdateFrame(void* param)
{
Graphics* graphics = (Graphics*)param;
graphics->update();
}
///
// Create a shader object, load the shader source, and
// compile the shader.
//
GLuint LoadShader(GLenum type, const GLchar *shaderSrc)
{
GLuint shader;
GLint compiled;
// Create the shader object
shader = glCreateShader(type);
if(shader == 0)
{
cerr << "Could not create OpenGL shader " << endl;
return 0;
}
// Load the shader source
glShaderSource(shader, 1, &shaderSrc, NULL);
// Compile the shader
glCompileShader(shader);
// Check the compile status
glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled);
if(!compiled)
{
GLint infoLen = 0;
glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &infoLen);
if(infoLen > 1)
{
char* infoLog = (char*)malloc(sizeof(char) * infoLen);
glGetShaderInfoLog(shader, infoLen, NULL, infoLog);
SDL_Log("Error compiling shader:\n%s\n", infoLog);
free(infoLog);
}
glDeleteShader(shader);
return 0;
}
return shader;
}
///
// Initialize the shader and program object
//
int Init()
{
const char vertexShaderString[] =
"attribute vec4 vPosition; \n"
"void main() \n"
"{ \n"
" gl_Position = vPosition; \n"
"} \n";
const char fragmentShaderString[] =
"precision mediump float;\n"\
"void main() \n"
"{ \n"
" gl_FragColor = vec4 (1.0, 0.0, 0.0, 1.0);\n"
"} \n";
GLuint vertexShader;
GLuint fragmentShader;
GLint linked;
vertexShader = LoadShader (GL_VERTEX_SHADER, vertexShaderString);
fragmentShader = LoadShader (GL_FRAGMENT_SHADER, fragmentShaderString);
programObject = glCreateProgram();
if (programObject == 0) {
cerr << "Could not create OpenGL program" << endl;
return 0;
}
glAttachShader (programObject, vertexShader);
glAttachShader (programObject, fragmentShader);
glBindAttribLocation (programObject, 0, "vPosition");
glLinkProgram (programObject);
glGetProgramiv (programObject, GL_LINK_STATUS, &linked);
if (!linked) {
GLint infoLen = 0;
glGetProgramiv (programObject, GL_INFO_LOG_LENGTH, &infoLen);
if (infoLen > 1) {
char* infoLog = (char*) malloc (sizeof (char) * infoLen);
glGetProgramInfoLog (programObject, infoLen, NULL, infoLog);
cerr << "Error linking program: " << infoLog << endl;
free (infoLog);
}
glDeleteProgram (programObject);
return 0;
}
glClearColor (0.0f, 0.0f, 0.0f, 1.0f);
return true;
}
int EventFilter(void* userdata, SDL_Event* event)
{
switch (event->type)
{
case SDL_FINGERMOTION:
SDL_Log("Finger Motion");
return 0;
case SDL_FINGERDOWN:
SDL_Log("Finger Down");
return 0;
case SDL_FINGERUP:
SDL_Log("Finger Up");
return 0;
}
return 1;
}
int main(int argc, char** argv)
{
/* initialize SDL */
if (SDL_Init(SDL_INIT_VIDEO) < 0)
{
printf("Could not initialize SDL\n");
return 1;
}
SDL_DisplayMode displayMode;
SDL_GetDesktopDisplayMode(0, &displayMode);
/* create window and renderer */
SDL_Window* window = SDL_CreateWindow(NULL, 0, 0, displayMode.w, displayMode.h, SDL_WINDOW_OPENGL | SDL_WINDOW_FULLSCREEN | SDL_WINDOW_RESIZABLE);
if (!window) {
printf("Could not initialize Window\n");
return 1;
}
auto gl = SDL_GL_CreateContext(window);
if (!Init()) {
cerr << "Error initializing OpenGL" << endl;
return 1;
}
unique_ptr<Graphics> graphics = unique_ptr<Graphics>(new Graphics(window));
SDL_iPhoneSetAnimationCallback(window, 1, UpdateFrame, graphics.get());
SDL_AddEventWatch(EventFilter, NULL);
//Game Loop
SDL_Event event;
auto done = false;
while (!done)
{
SDL_PumpEvents();
while (SDL_PollEvent(&event))
{
switch (event.type)
{
case SDL_QUIT:
done = true;
break;
case SDL_APP_DIDENTERFOREGROUND:
SDL_Log("SDL_APP_DIDENTERFOREGROUND");
break;
case SDL_APP_DIDENTERBACKGROUND:
SDL_Log("SDL_APP_DIDENTERBACKGROUND");
break;
case SDL_APP_LOWMEMORY:
SDL_Log("SDL_APP_LOWMEMORY");
break;
case SDL_APP_TERMINATING:
SDL_Log("SDL_APP_TERMINATING");
break;
case SDL_APP_WILLENTERBACKGROUND:
SDL_Log("SDL_APP_WILLENTERBACKGROUND");
break;
case SDL_APP_WILLENTERFOREGROUND:
SDL_Log("SDL_APP_WILLENTERFOREGROUND");
break;
case SDL_WINDOWEVENT:
{
switch (event.window.event)
{
case SDL_WINDOWEVENT_RESIZED:
{
SDL_Log("Window %d resized to %dx%d", event.window.windowID, event.window.data1, event.window.data2);
break;
}
}
}
}
}
}
SDL_GL_DeleteContext(gl);
// Done! Close the window, clean-up and exit the program.
SDL_DestroyWindow(window);
SDL_Quit();
return 0;
}
也許我失去了一些東西的代碼，任何幫助，將不勝感激。 謝謝， 哈立德
您是否嘗試過使用'glGetError（）'來查找OpenGL發出的錯誤（如果有的話）？所有你需要做的就是在'shader = glCreateShader（type）;'之前調用'glGetError（）;'然後再次調用它，但是將結果賦給一個變量'GLenum err = glGetError（）;'從那裏你可以使用'gluErrorString（GLenum err）;'獲取更多信息。 – Zammalad 2014-10-03 22:29:37
我得到錯誤GL_INVALID_OPERATION，而我沒有使用glu我正在使用SDL – 2014-10-04 13:38:40
如果刪除任何與着色器有關的事情，你至少能夠渲染一個空白窗口？ – Zammalad 2014-10-04 17:38:40