请教cuda图像缓冲区绑定问题

[jywzzz]

那个cuda生产一组顶点集，然后用openGL显示的例子我看过了。

现在我想，就用cuda产生一张图片，然后用openGL显示，不知道为什么总是黑色。

代码如下，谢谢。

1、main.cpp

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <gl/glew.h>
#include <gl/glut.h>

#include <cuda_runtime.h>
#include <cuda_gl_interop.h>
#include <vector_types.h>

#include "gen.h"

#define BUFFER_OFFSET(bytes)	((GLubyte*)NULL + (bytes))

#define imgWidth 256
#define imgHeight 256

static GLfloat zoomFactor = 1.0;
static GLuint pixelBuffer;
struct cudaGraphicsResource* cuda_vbo_resource;

void init(){
	GLenum err = glewInit();
	if(GLEW_OK != err)
		printf("Glew Error !\n");

	glClearColor(0, 0, 0, 0);
	glShadeModel(GL_FLAT);

	glGenBuffersARB(1, &pixelBuffer);
	glBindBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB, pixelBuffer);
	glBufferDataARB(GL_PIXEL_UNPACK_BUFFER_ARB, imgWidth * imgHeight * sizeof(GLubyte) * 4,
		NULL, GL_STREAM_DRAW_ARB);
	glBindBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB, 0);

	cudaGraphicsGLRegisterBuffer(&cuda_vbo_resource, pixelBuffer, cudaGraphicsMapFlagsWriteDiscard);
}

void display(){
	GLuint *dptr;
	GLuint num_bytes; 

	cudaGraphicsMapResources(1, &cuda_vbo_resource, 0); 
	cudaGraphicsResourceGetMappedPointer((void**)&dptr,
		&num_bytes, cuda_vbo_resource); 

	cudaMemset(dptr, 0, imgWidth*imgHeight*4);

	// Lauch kernel
	launch_kernel(dptr, 0, imgWidth, imgHeight);

	// Unmap buffer object 
	cudaGraphicsUnmapResources(1, &cuda_vbo_resource, 0); 

	glClear(GL_COLOR_BUFFER_BIT);

	glDisable(GL_DEPTH_TEST);
	glRasterPos2i(0, 0);
	glBindBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB, pixelBuffer);
	glDrawPixels(imgWidth, imgHeight, GL_RGBA, GL_UNSIGNED_BYTE, BUFFER_OFFSET(0));
	glBindBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB, 0);

	glutSwapBuffers();
	glutPostRedisplay();
}

void reshape(int w, int h){
	glViewport(0, 0, (GLsizei)w, (GLsizei)h);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluOrtho2D(0, (GLdouble)w, 0, (GLdouble)h);
}

void keyboard(unsigned char key, int x, int y){
	switch(key){
		case ' ':
			glutPostRedisplay();
			break;
		case 27:
			exit(0);
			break;
		default:
			break;
	}
}

int main(int argc, char** argv){
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
	glutInitWindowSize(440, 440);
	glutInitWindowPosition(100, 100);
	glutCreateWindow("List");

	init();
	glutDisplayFunc(display);
	glutReshapeFunc(reshape);
	glutKeyboardFunc(keyboard);

	glutMainLoop();
	
	cudaGraphicsUnregisterResource(cuda_vbo_resource);
	glBindBufferARB(1, pixelBuffer);
	glDeleteBuffersARB(1, &pixelBuffer);

	return 0;
}

2、gen.h

#ifndef __KERNER__JYWZZZ
#define __KERNER__JYWZZZ

extern "C" void launch_kernel(unsigned int* positions, 
							  float anim, 
							  unsigned int width, 
							  unsigned int height);

#endif

3、gen.cu

#include "gen.h"

__global__ void createVertices(unsigned int* positions, float anim, unsigned int width, unsigned int height)
{
	unsigned int x = blockIdx.x * blockDim.x + threadIdx.x;
	unsigned int y = blockIdx.y * blockDim.y + threadIdx.y; 
	
	// Write positions 
	positions[y * width + x] = 0xff0000ff; 
}

void launch_kernel(unsigned int* positions, float anim, unsigned int width, unsigned int height){
	// Execute kernel
	dim3 dimBlock(16, 16, 1); 
	dim3 dimGrid(width / dimBlock.x, height / dimBlock.y, 1); 
	createVertices<<<dimGrid, dimBlock>>>(positions, anim, width, height); 
}

[无心人_过过小日子]

参考sdk中simpleGL的代码.

[无心人_过过小日子]

[Quote=引用 2 楼 jywzzz 的回复:]
2楼，simpleGL就是我说的那个cuda生成顶点集，然后opengl显示的那个，话说您有没有真正看过？
[/Quote]

我机器上编译/执行很好啊.没问题的.呵呵.
从sample改过来,是一步步来的.到哪步不对了,再想办法解决.这才是正确的办法.

[jywzzz]

2楼，simpleGL就是我说的那个cuda生成顶点集，然后opengl显示的那个，话说您有没有真正看过？

[jywzzz]

我自己解决了，OpenGL红宝书好好看了一遍。