Hi DaneLLL,
Here is the sample code I’m using to debug this problem:
#include <EGL/egl.h>
#include <GLES2/gl2.h>
#include <GLES2/gl2ext.h>
#include <stdio.h>
#include <stdlib.h>
#include "/home/nvidia/tegra_multimedia_api/include/nvbuf_utils.h"
const char * vertex_shader = R"glsl(
#version 100
attribute vec2 position;
attribute vec2 tex_coord;
varying vec2 tex_coord_var;
uniform mat4 transform_matrix;
void main()
{
tex_coord_var = tex_coord;
gl_Position = transform_matrix * vec4(position, 0.0, 1.0);
}
)glsl";
const char * fragment_shader = R"glsl(
#version 100
precision mediump float;
varying vec2 tex_coord_var;
uniform sampler2D tex;
void main()
{
vec4 tex_color = texture2D(tex, tex_coord_var);
gl_FragColor = vec4(tex_color.r, tex_color.g, tex_color.b, 1.0);
}
)glsl";
int main()
{
int input_image_width = 64;
int input_image_height = 64;
unsigned char * input_image_data = malloc(input_image_width*input_image_height*4*sizeof(char));
int output_image_width = 64;
int output_image_height = 64;
/* 4 color checkers */
for (int i = 0; i< input_image_height; i++){
for (int j = 0; j< input_image_width; j++){
unsigned char R = 0;
unsigned char G = 0;
unsigned char B = 0;
unsigned char A = 0;
int imod = i%2;
int jmod = j%2;
if (!imod && !jmod) R=255;
if (!imod && jmod) G=255;
if (imod && !jmod) B=255;
if (imod && jmod){
R=255;
G=255;
B=255;
}
*(char*)(input_image_data+(i*input_image_width*4+j*4)) = R;
*(char*)(input_image_data+(i*input_image_width*4+j*4)+1) = G;
*(char*)(input_image_data+(i*input_image_width*4+j*4)+2) = B;
*(char*)(input_image_data+(i*input_image_width*4+j*4)+3) = A;
}
}
/* save the input image as a raw */
FILE * fpin = fopen ("in.raw", "wb+");
fwrite (input_image_data, input_image_width * input_image_height * 4, 1, fpin);
fclose (fpin);
GLuint tex[2];
GLuint fbo, vbo, ebo, v_shader, f_shader, shader_program;
EGLDisplay egl_display;
EGLSurface egl_surface;
EGLContext egl_context;
/* EGL context creation */
EGLConfig egl_config;
EGLint matching_configs;
const EGLint config_attrib_list[] = {
EGL_SURFACE_TYPE, EGL_PBUFFER_BIT,
EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
EGL_NONE
};
const EGLint pbuffer_attrib_list[] = {
EGL_WIDTH, output_image_width,
EGL_HEIGHT, output_image_height,
EGL_NONE,
};
const EGLint context_attrib_list[] = {
EGL_CONTEXT_CLIENT_VERSION, 2,
EGL_NONE
};
egl_display = eglGetDisplay ((EGLNativeDisplayType) 0);
eglInitialize (egl_display, 0, 0);
eglBindAPI (EGL_OPENGL_ES_API);
eglChooseConfig (egl_display, config_attrib_list, &egl_config, 1, &matching_configs);
egl_surface = eglCreatePbufferSurface (egl_display, egl_config, pbuffer_attrib_list);
egl_context = eglCreateContext (egl_display, egl_config, EGL_NO_CONTEXT, context_attrib_list);
eglMakeCurrent (egl_display, egl_surface, egl_surface, egl_context);
/* OpenGL init */
glViewport (0, 0, output_image_width, output_image_height);
glGenFramebuffers (1, &fbo);
glGenTextures (2, tex);
glGenBuffers (1, &vbo);
glGenBuffers (1, &ebo);
shader_program = glCreateProgram ();
v_shader = glCreateShader (GL_VERTEX_SHADER);
f_shader = glCreateShader (GL_FRAGMENT_SHADER);
glShaderSource (v_shader, 1, &vertex_shader, NULL);
glShaderSource (f_shader, 1, &fragment_shader, NULL);
glCompileShader (v_shader);
glCompileShader (f_shader);
glAttachShader (shader_program, v_shader);
glAttachShader (shader_program, f_shader);
/* OpenGL run */
GLuint vertex_position, texture_position;
GLint transform_matrix;
const GLfloat vertices[] = {
-1.0f, 1.0f, 0.0f, 1.0f,
1.0f, 1.0f, 1.0f, 1.0f,
1.0f, -1.0f, 1.0f, 0.0f,
-1.0f, -1.0f, 0.0f, 0.0f
};
const GLuint elements[] = {
0, 1, 2,
2, 3, 0
};
GLfloat mat[] = {
1.0, 0.0, 0.0, 0.0,
0.0, 1.0, 0.0, 0.0,
0.0, 0.0, 1.0, 0.0,
0.0, 0.0, 0.0, 1.0
};
glBindFramebuffer (GL_FRAMEBUFFER, fbo);
glBindBuffer (GL_ARRAY_BUFFER, vbo);
glBufferData (GL_ARRAY_BUFFER, sizeof (vertices), vertices, GL_STATIC_DRAW);
glBindBuffer (GL_ELEMENT_ARRAY_BUFFER, ebo);
glBufferData (GL_ELEMENT_ARRAY_BUFFER, sizeof (elements), elements, GL_STATIC_DRAW);
glLinkProgram (shader_program);
glUseProgram (shader_program);
transform_matrix = glGetUniformLocation (shader_program, "transform_matrix");
glUniformMatrix4fv (transform_matrix, 1, GL_FALSE, mat);
vertex_position = glGetAttribLocation (shader_program, "position");
glEnableVertexAttribArray (vertex_position);
glVertexAttribPointer (vertex_position, 2, GL_FLOAT, GL_FALSE, 4 * sizeof (GLfloat), 0);
texture_position = glGetAttribLocation (shader_program, "tex_coord");
glEnableVertexAttribArray (texture_position);
glVertexAttribPointer (texture_position, 2, GL_FLOAT, GL_FALSE, 4 * sizeof (GLfloat), (void *) (2 * sizeof (GLfloat)));
glBindTexture (GL_TEXTURE_2D, tex[0]);
glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA, input_image_width, input_image_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, input_image_data);
glUniform1i (glGetUniformLocation (shader_program, "tex"), 0);
glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
/* EGLImage creation*/
int dmabuf_fd;
void * virtual_addr;
EGLImageKHR egl_image;
PFNGLEGLIMAGETARGETTEXTURE2DOESPROC EGLImageTargetTexture2DOES;
/* NvBufferLayout_Pitch isn't working */
NvBufferCreate(&dmabuf_fd, output_image_width, output_image_height, NvBufferLayout_BlockLinear, NvBufferColorFormat_ABGR32);
NvBufferMemMap(dmabuf_fd, 0, NvBufferMem_Read_Write, &virtual_addr);
egl_image = NvEGLImageFromFd (egl_display, dmabuf_fd);
EGLImageTargetTexture2DOES = (PFNGLEGLIMAGETARGETTEXTURE2DOESPROC) eglGetProcAddress ("glEGLImageTargetTexture2DOES");
glBindTexture (GL_TEXTURE_2D, tex[1]);
EGLImageTargetTexture2DOES (GL_TEXTURE_2D, (GLeglImageOES) egl_image);
NvBufferMemSyncForDevice (dmabuf_fd, 0, virtual_addr);
glFramebufferTexture2D (GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tex[1], 0);
glBindTexture (GL_TEXTURE_2D, tex[0]);
glClearColor (0.0f, 0.0f, 0.0f, 1.0f);
glClear (GL_COLOR_BUFFER_BIT);
glDrawElements (GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
glFinish ();
NvBufferMemSyncForCpu (dmabuf_fd, 0, virtual_addr);
/*
* If I use glReadPixels here the output is OK
* glReadPixels (0, 0, output_image_width, output_image_height, GL_RGBA, GL_UNSIGNED_BYTE, virtual_addr);
*
*/
/* save the output image as a raw */
FILE * fpout = fopen ("out.raw", "w+");
fwrite (virtual_addr, output_image_width * output_image_height * 8, 1, fpout);
fclose (fpout);
/* OpenGL stop */
NvDestroyEGLImage (egl_display, egl_image);
NvBufferMemUnMap (dmabuf_fd, 0, virtual_addr);
NvBufferDestroy (dmabuf_fd);
glDeleteFramebuffers (1, &fbo);
glDeleteTextures (2, tex);
glDeleteBuffers (1, &vbo);
glDeleteBuffers (1, &ebo);
glDeleteShader (v_shader);
glDeleteShader (f_shader);
glDeleteProgram (shader_program);
eglDestroyContext (egl_display, egl_context);
eglDestroySurface (egl_display, egl_surface);
eglTerminate (egl_display);
free(input_image_data);
return 0;
}
