1
我試圖用着色器使用VAO的+ VBO + IBO，但沒有繪製任何對象。我不知道我錯過了什麼。我對C++和GLSL相當陌生，所以我不確定我是否總是用C++搞砸了某些東西，或者如果我無法正確處理OpenGL上下文？VAO + IBO與GLSL着色器的使用
主要功能（用於處理窗口創建代碼丟失。如果你認爲你可能需要檢查它爲好，只是讓我知道。）：
int main(int argc, char *argv[])
{
//INIT SDL
SDL_Init(SDL_INIT_VIDEO);
SDL_CreateWindowAndRenderer(400, 300, SDL_WINDOW_OPENGL, &displayWindow, &displayRenderer);
SDL_GetRendererInfo(displayRenderer, &displayRendererInfo);
/*TODO: Check that we have OpenGL */
if ((displayRendererInfo.flags & SDL_RENDERER_ACCELERATED) == 0 || (displayRendererInfo.flags & SDL_RENDERER_TARGETTEXTURE) == 0) {}
SDL_GL_CreateContext(displayWindow);
//SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
glewInit();
int error = glGetError();
if (error != GL_NO_ERROR){ std::cout << "Error during glewInit call: " << error << "\n"; };
//glEnable(GL_DEBUG_OUTPUT);
Display_InitGL();
error = glGetError();
if (error != GL_NO_ERROR){ std::cout << "Error during Display init: " << error << "\n"; };
Display_SetViewport(400, 300);
error = glGetError();
if (error != GL_NO_ERROR){ std::cout << "Error during Display Set Viewport Issue: " << error << "\n"; };
// SET UP TEST OBJ
MainChar *player = new MainChar();
player->MainChar_VBO_Func();
GLushort size = player->MainChar_VBO_IndexBuffer_Func();
float count = 0.0;
// END SET UP OF TEST OBJ
GLint *length = new GLint;
const char* vertShdr = readFile("C:\\Users\\JRFerrell\\Documents\\Visual Studio 2013\\Projects\\GLEW Practice\\vertShader.vs", *length);
std::cout << vertShdr;
GLuint vertShaderId = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertShaderId, 1, &vertShdr, length);
std::cout << "\n\nLength: " << *length;
glCompileShader(vertShaderId);
GLint *length2 = new GLint;
const char* fragShdr = readFile("C:\\Users\\JRFerrell\\Documents\\Visual Studio 2013\\Projects\\GLEW Practice\\fragShader.fs", *length2);
GLint fragShaderId = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragShaderId, 1, &fragShdr, length2);
glCompileShader(fragShaderId);
GLuint shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertShaderId);
error = glGetError();
if (error != GL_NO_ERROR){ std::cout << "Error during glAttachShader: " << error << "\n"; };
glAttachShader(shaderProgram, fragShaderId);
error = glGetError();
if (error != GL_NO_ERROR){ std::cout << "Error during glAttachShader: " << error << "\n"; };
glBindAttribLocation(shaderProgram, 0, "in_Position");
glBindAttribLocation(shaderProgram, 1, "in_Normal");
glLinkProgram(shaderProgram);
error = glGetError();
if (error != GL_NO_ERROR){ std::cout << "Error during glLinkProgram: " << error << "\n"; };
// END SHADER PROGRAM DEFINITION
//Check info log for errors:
int Len = 0;
char *Buffer = nullptr;
glGetShaderiv(vertShaderId, GL_INFO_LOG_LENGTH, &Len);
Buffer = new char[Len];
glGetShaderInfoLog(vertShaderId, Len, &Len, Buffer);
std::cout << "Vertex Log:" << std::endl << Buffer << std::endl;
delete[] Buffer;
glGetShaderiv(fragShaderId, GL_INFO_LOG_LENGTH, &Len);
Buffer = new char[Len];
glGetShaderInfoLog(fragShaderId, Len, &Len, Buffer);
std::cout << "Fragment Log:" << std::endl << Buffer << std::endl;
delete[] Buffer;
glGetProgramiv(shaderProgram, GL_INFO_LOG_LENGTH, &Len);
Buffer = new char[Len];
glGetProgramInfoLog(shaderProgram, Len, &Len, Buffer);
std::cout << "Shader Log:" << std::endl << Buffer << std::endl;
delete[] Buffer;
// Create VAO. Don't forget to enable all necessary states because the VAO starts with default state, cleaning all states prev called to do so.
GLuint VaoId;
glGenVertexArrays(1, &VaoId);
glBindVertexArray(VaoId);
// Bind buffers & set-up VAO vertex pointers
glBindBuffer(GL_ARRAY_BUFFER, player->vboID);
error = glGetError();
if (error != GL_NO_ERROR){ std::cout << "Error glBindBuffer-vboID: " << error << "\n"; }
glEnableClientState(GL_VERTEX_ARRAY);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * GL_FLOAT, (const GLvoid *)0);
glEnableVertexAttribArray(0);
// Set-up VAO normal pointers
error = glGetError();
if (error != GL_NO_ERROR){ std::cout << "Error glBindBuffer-vbo init: " << error << "\n"; }
glEnableClientState(GL_NORMAL_ARRAY);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * GL_FLOAT, (void*)(3 * sizeof(GL_FLOAT)));
glEnableVertexAttribArray(1);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, player->vboIndexID);
GLint maxLength, nAttribs;
glGetProgramiv(shaderProgram, GL_ACTIVE_ATTRIBUTES, &nAttribs);
glGetProgramiv(shaderProgram, GL_ACTIVE_ATTRIBUTES, &maxLength);
//std::cout << "\nmax length: " << maxLength << "\nnAttribs: " << nAttribs;
glBindVertexArray(0);
error = glGetError();
if (error != GL_NO_ERROR){ std::cout << "Error glBindVertexArray: " << error << "\n"; };
// End VAO init
while (1){
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
error = glGetError();
if (error != GL_NO_ERROR){ std::cout << "Error glClearColor: " << error << "\n"; };
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
error = glGetError();
if (error != GL_NO_ERROR){ std::cout << "Error in glClear: " << error << "\n"; };
glLoadIdentity();
glUseProgram(shaderProgram);
glBindVertexArray(VaoId);
glDrawElements(GL_TRIANGLES, size, GL_UNSIGNED_SHORT, 0);
glUseProgram(0);
glBindVertexArray(0);
SDL_GL_SwapWindow(displayWindow);
count -= .1;
}
SDL_Delay(5000);
SDL_Quit();
return 0;
}
::着色器代碼::
頂點着色器：
#version 400
in vec3 in_Position;
in vec3 in_Normal;
void main()
{
gl_Position = vec4(in_Position, 1.0);
}
片段着色器：
#version 400
out vec4 FragColor;
void main()
{
FragColor = vec4(0.0f, 0.5f, 1.0f, 1.0f);
}
我的確在這裏看過類似的問題，他們確實幫我解決了一些可能的問題，但到目前爲止，他們顯然沒有證明可以幫助我啓動代碼。我還問了一些其他人在gamedev.net實時聊天，但他們似乎無法看到我出錯的地方。我修正了一個聲明glDoubles而不是浮點的可能的問題，但是實際上沒有vao和着色器，所以這不是（也不可能是）整個或部分問題。
是的......我對glLoadIdentity調用有一個偷偷摸摸的懷疑，但我認爲這個啓用是我看到的其他tut所必需的。我一直試圖通過查看示例來學習，但顯然我需要更好地瞭解我正在使用的規範。其次，我確實使用glBindAttribLocation。我在連接着色器後立即這樣做，並在將它們鏈接到我的程序之前：glBindAttribLocation（shaderProgram，0，「in_Position」）; glBindAttribLocation（shaderProgram，1，「in_Normal」）; – JRFerrell
此外，無論出於何種原因，我的上下文都返回了一個警告，告訴我佈局限定符已被棄用，因此我將其取出，並用bindattribloc調用替換它。 – JRFerrell
另外，如果我在glVertexAttribPointer之前或之後調用glEnableVertexAttribArray，只要我最終調用它，這有什麼關係嗎？我看到了混合樣本，有人說他們的版本工作，所以我只是想檢查。 – JRFerrell