带有VS C ++ Rainbow Triangle的OpenGL ES 2 [英] OpenGL ES 2 with VS C++ Rainbow Triangle
问题描述
我想问一件事:
我有一个使用OpenGL ES 2和C ++绘制Red Triangle的程序，我的问题是
如何改善程序以创建Rainbow Triangle?"
这是我在程序中用来创建Red Triangle的代码:
Hi, I wanna ask something :
I got a program that draw Red Triangle using OpenGL ES 2 and C++ and my question is
"How could I improved my program in order to create Rainbow Triangle?"
Here''s the code that I used in my program to create Red Triangle:
#include <stdlib.h>
#include "esUtil.h"
#include <stdio.h>
typedef struct
{
// Handle to a program object
GLuint programObject;
} UserData;
///
// Create a shader object, load the shader source, and
// compile the shader.
//
GLuint LoadShader ( GLenum type, const char *shaderSrc )
{
GLuint shader;
GLint compiled;
// Create the shader object
shader = glCreateShader ( type );
if ( shader == 0 )
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 = malloc (sizeof(char) * infoLen );
glGetShaderInfoLog ( shader, infoLen, NULL, infoLog );
esLogMessage ( "Error compiling shader:\n%s\n", infoLog );
free ( infoLog );
}
glDeleteShader ( shader );
return 0;
}
return shader;
}
///
// Initialize the shader and program object
//
int Init ( ESContext *esContext )
{
UserData *userData = esContext->userData;
GLbyte vShaderStr[] =
"attribute vec4 vPosition; \n"
"void main() \n"
"{ \n"
" gl_Position = vPosition; \n"
"} \n";
GLbyte fShaderStr[] =
"precision mediump float; \n"
"void main() \n"
"{ \n"
" gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0), \n"
" (0.0 , 1.0 , 0.0 , 1.0),\n"
" (0.0 , 0.0 , 0.1 , 1.0); \n"
"} \n";
GLuint vertexShader;
GLuint fragmentShader;
GLuint programObject;
GLint linked;
/*UserData *userData = esContext->userData;
GLbyte vShaderStr[] =
"attribute vec4 a_Position; \n"
"attribute vec2 a_texCoord; \n"
"varying vec2 v_texCoord; \n"
"void main() \n"
"{ int i; \n"
"//for (i=0;i<=1;i++) \n"
" // gl_Position = vPosition; \n"
"gl_Position = a_position; \n"
"v_texCoord=a_texCoord; \n"
"} \n";
GLbyte fShaderStr[] =
"precision mediump float;\n"
"varying vec2 v_texCoord;\n"
"uniform sampler2D s_texture;\n"
"void main(){ \n"
"//for (i=0;i<=1;i++) \n"
"//gl_FragColor = vec4 ( 1.0, 0.0, 0.0, 1.0);\n"
"//gl_FragColor = vec4 (1,1,1,0);\n"
"gl_FragColor=texture2D(s_texture, v_texCoord);\n"
"} \n";*/
//GLuint vertexShader;
//GLuint fragmentShader;
//GLuint programObject;
//GLint linked;
// Load the vertex/fragment shaders
vertexShader = LoadShader ( GL_VERTEX_SHADER, vShaderStr );
fragmentShader = LoadShader ( GL_FRAGMENT_SHADER, fShaderStr );
// Create the program object
programObject = glCreateProgram ( );
if ( programObject == 0 )
return 0;
glAttachShader ( programObject, vertexShader );
glAttachShader ( programObject, fragmentShader );
// Bind vPosition to attribute 0
glBindAttribLocation ( programObject, 0, "vPosition" );
// Link the program
glLinkProgram ( programObject );
// Check the link status
glGetProgramiv ( programObject, GL_LINK_STATUS, &linked );
if ( !linked )
{
GLint infoLen = 0;
glGetProgramiv ( programObject, GL_INFO_LOG_LENGTH, &infoLen );
if ( infoLen > 1 )
{
char* infoLog = malloc (sizeof(char) * infoLen );
glGetProgramInfoLog ( programObject, infoLen, NULL, infoLog );
esLogMessage ( "Error linking program:\n%s\n", infoLog );
free ( infoLog );
}
glDeleteProgram ( programObject );
return FALSE;
}
// Store the program object
userData->programObject = programObject;
glClearColor ( 0.0f, 0.0f, 0.0f, 0.0f );//background
return TRUE;
}
///
// Draw a triangle using the shader pair created in Init()
//
void Draw ( ESContext *esContext )
{
static float transY = 0.0f;
GLuint textureID;
UserData *userData = esContext->userData;
GLubyte warna [] ={1.0, 0.0, 0.0, 1.0,
0.0, 1.0, 0.0, 1.0,
0.0, 0.0, 0.1, 1.0};
GLfloat vVertices[] = { 0.0f, 0.5f, 0.0f,
-0.5f, -0.5f, 0.0f,
0.5f, -0.5f, 0.0f };
/* GLubyte warna [] ={1.0, 0.0, 0.0, 1.0,
0.0, 1.0, 0.0, 1.0,
0.0, 0.0, 0.1, 1.0};*/
/* glPixelStorei(GL_UNPACK_ALIGNMENT ,1);
glGenTextures(1, &textureID);
glBindTexture(GL_TEXTURE_2D, textureID);
glTexImage2D(GL_TEXTURE_2D,0,GL_RGB,2,2,0,GL_RGB,GL_UNSIGNED_BYTE,warna);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);*/
// Set the viewport
glViewport ( 0, 0, esContext->width, esContext->height );
// Clear the color buffer
glClear ( GL_COLOR_BUFFER_BIT );
// Use the program object
glUseProgram ( userData->programObject );
// Load the vertex data
glVertexAttribPointer ( 0, 3, GL_FLOAT, GL_FALSE, 0, vVertices );
//glVertexAttribPointer(ATTRIB_COLOR, 4, GL_UNSIGNED_BYTE, 1, 0, squareColors);
// glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,0,warna);
glEnableVertexAttribArray(0);
// glEnableClientState();
glDrawArrays ( GL_TRIANGLES, 0, 3 );
eglSwapBuffers ( esContext->eglDisplay, esContext->eglSurface );
}
int main ( int argc, char *argv[] )
{
ESContext esContext;
UserData userData;
esInitContext ( &esContext );
esContext.userData = &userData;
esCreateWindow ( &esContext, "Hello Triangle", 320, 240, ES_WINDOW_RGB );
if ( !Init ( &esContext ) )
return 0;
esRegisterDrawFunc ( &esContext, Draw );
esMainLoop ( &esContext );
}
我正在使用VS C ++ 2008和OpenGL ES2.
我应该在该代码中更改或添加什么?
预先感谢，
最好的问候
I am using VS C++ 2008 and OpenGL ES 2.
What should I change or add into that code?
Thanks in advance,
Best regards
推荐答案
Have n't以前没有使用glDrawArrays，尽管看起来问题是您的fragmentShader程序包含以下文本:
Haven''t used glDrawArrays before, though it seems the problem is that your fragmentShader program contains the following text:
gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0), \n"
" (0.0, 1.0 , 0.0 , 1.0),\n"
" (0.0, 0.0 , 0.1 , 1.0);
我在网上找不到能够像这样分配gl_FragColor的单个引用.
我会假设三角形都是red，因为那是颜色(1.0、0.0、0.0、1.0).使用glDrawArrays时，我希望看到您提供的数组包含(a)垂直坐标(b)垂直法线(c)垂直颜色(d)tex坐标.
快速浏览一下文档表明情况确实如此.您刚刚使用过glVertexAttribPointer，而我认为您应该制作另一个数组来保存每个顶点的颜色，并通过使用glColorPointer来让OpenGL知道它.
I can''t find a single reference on the net to being able to assign gl_FragColor like this.
I would assume that the triangle is all red because that''s the color (1.0, 0.0, 0.0, 1.0). When using glDrawArrays, I would expect to see that you supply arrays holding (a) vert coords (b) vert normals (c) vert-colors (d) tex-coords.
A quick look at the docs suggests this to be the case. You''ve just used glVertexAttribPointer, while I think you should make another array that holds the colours of each of the verts and let OpenGL know about it through the use of glColorPointer.
哦，我昨晚以某种方式解决了问题:
这里是方法:
而不是使用这个:''
Oh, somehow I solved it last night :
here''s how :
Instead of using this :''
"attribute vec4 vPosition; \n"
"void main() \n"
"{ \n"
" gl_Position = vPosition; \n"
"} \n";
GLbyte fShaderStr[] =
"precision mediump float; \n"
"void main() \n"
"{ \n"
" gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0), \n"
" (0.0 , 1.0 , 0.0 , 1.0),\n"
" (0.0 , 0.0 , 0.1 , 1.0); \n"
"} \n";
我用这个:
I use this :
"attribute vec4 vPosition; \n"
"attribute vec4 a_color; \n"
"varying vec4 v_color; \n"
"void main() \n"
"{ \n"
" v_color = a_color; \n"
" gl_Position = vPosition; \n"
"}\n";
GLbyte fShaderStr[] =
"precision mediump float; \n"
"varying vec4 v_color; \n"
"void main (void) \n"
"{ \n"
" gl_FragColor = v_color; \n"
"}";
我修改了一些代码:
新变量:
And I modify some of my codes :
New variables :
GLint attColor;
GLint attPosition;
..
..
attPosition = glGetAttribLocation(programObject, "vPosition");
attColor = glGetAttribLocation(programObject, "a_color");
更新我的绘图功能:
Updating my draw function :
...
..
glVertexAttribPointer(attPosition, 3, GL_FLOAT, GL_FALSE, 0, vVertices);
glVertexAttribPointer(attColor, 4, GL_FLOAT, GL_FALSE, 0, warna);
glEnableVertexAttribArray(attPosition);
glEnableVertexAttribArray(attColor);
..
..
和中提琴！，我的窗户上有彩虹三角.
无论如何，感谢您的关注并回复大家.
最好的问候，
newmessage
PS:任何人都需要我的源代码(可能)，只是PM我.我会寄给您.
And viola!, I got Rainbow Triangle on my windows.
Anyhow, Thanks for the concern and reply to all of you.
Best Regards,
newmessage
PS: anyone need my source code (probably), just PM me. I''ll mail you .
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