loading bmp images OPENGL 3.x - only loading one pixel? - opengl

Question

So Im having a bit of trouble loading texture images. I am not exactly sure what I could be doing wrong. It seems to only be reading the last pixel and I am not sure why?
Any help is appreciated. Here is my code:
#include "Angel.h"
#include <glew.h>
#include <glut.h>
#include <typeinfo>
#include <iostream>
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
using namespace std;
vec4 gridLines[] = {
vec4(-0.5, -0.5, 0.0, 1.0), //v1
vec4(0.5, -0.5, 0.0, 1.0), //v2
vec4(-0.5, 0.5, 0.0, 1.0), //v3
vec4(0.5, 0.5, 0.0, 1.0), //v4
};
GLuint vertexID[3];
GLuint bufferID2;
GLuint ProjectionLocation, ModelViewLocation;
mat4 instance;
//----------------------------------------------------------------------------
//----------------------------------------------------------------------------
float
roundTo(float value, int digits)//Ensures rounding is done correct
{
//check to see if the value is very close to zero
if ((int)(value*10.0) == 0){
return 0.0;
}
double factor = pow(10.0, digits - ceil(log10(fabs(value))));
return round(value * factor) / factor;
}
void
init(void) //Initialize Buffers for all objects
{
//1. Load shaders and use the resulting shader program
GLuint program = InitShader("vshader81.glsl", "fshader81.glsl");
glUseProgram(program);
GLuint vPosition = glGetAttribLocation(program, "vPosition");
GLuint vColor = glGetAttribLocation(program, "vColor");
glGenVertexArrays(1, &vertexID[1]);
vec4 colors2[] = {
vec4(1.0, 1.0, 1.0, 1.0), //1
vec4(1.0, 1.0, 1.0, 1.0), //2
vec4(1.0, 1.0, 1.0, 1.0), //3
vec4(1.0, 1.0, 1.0, 1.0), //4
};
// Create and initialize a buffer object
glBindVertexArray(vertexID[1]);
glGenBuffers(1, &bufferID2);
glBindBuffer(GL_ARRAY_BUFFER, bufferID2);
glBufferData(GL_ARRAY_BUFFER, sizeof(gridLines)+sizeof(colors2), NULL, GL_STATIC_DRAW);
glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(gridLines), gridLines);
glBufferSubData(GL_ARRAY_BUFFER, sizeof(gridLines), sizeof(colors2), colors2);
glEnableVertexAttribArray(vPosition);
glVertexAttribPointer(vPosition, 4, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
GLuint textureid;
// Texture coordinates
vec4 tex_coords[] = {
vec4(-0.5, -0.5, 0.0, 1.0), //v1
vec4(0.5, -0.5, 0.0, 1.0), //v2
vec4(-0.5, 0.5, 0.0, 1.0), //v3
vec4(0.5, 0.5, 0.0, 1.0), //v4
};
glGenTextures(1, &textureid);
glBindTexture(GL_TEXTURE_2D, textureid);
/***********************************************/
const char * imagepath = "checkboard2.bmp";
// Data read from the header of the BMP file
unsigned char header[54]; // Each BMP file begins by a 54-bytes header
unsigned int dataPos; // Position in the file where the actual data begins
unsigned int width, height;
unsigned int imageSize; // = width*height*3
// Actual RGB data
unsigned char * data;
// Open the file
FILE * file = fopen(imagepath, "rb");
if (!file) { printf("Image could not be opened\n"); }
if (fread(header, 1, 54, file) != 54){ // If not 54 bytes read : problem
printf("Not a correct BMP file\n");
}
if (header[0] != 'B' || header[1] != 'M'){
printf("Not a correct BMP file\n");
}
cout << "great.." << endl;
// Read ints from the byte array
dataPos = *(int*)&(header[0x0A]);
imageSize = *(int*)&(header[0x22]);
cout << "Image Size: " << imageSize << endl;
width = *(int*)&(header[0x12]);
cout << "width: " << width << endl;
height = *(int*)&(header[0x16]);
// Some BMP files are misformatted, guess missing information
if (imageSize == 0) imageSize = width*height * 3; // 3 : one byte for each Red, Green and Blue component
if (dataPos == 0) dataPos = 54; // The BMP header is done that way
// Create a buffer
data = new unsigned char[imageSize];
// Read the actual data from the file into the buffer
fread(data, 1, imageSize, file);
//Everything is in memory now, the file can be closed
fclose(file);
//GLuint Texture = loadBMP_custom("brick_converted.bmp");
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_BGR, GL_UNSIGNED_BYTE, data);
// glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
// glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
//glActiveTexture(GL_TEXTURE0);
GLuint vTexCoord = glGetAttribLocation(program, "vTexCoord");
glEnableVertexAttribArray(vTexCoord);
glVertexAttribPointer(vTexCoord, 2, GL_FLOAT, GL_FALSE, 0,
BUFFER_OFFSET(sizeof(gridLines)));
glUniform1i(glGetUniformLocation(program, "texture"), 0);
//4. Bind all Buffers
glBindVertexArray(0);
//5.Set Background Color
glClearColor(0.5, 0.5, 0.5, 0.0); // background
}
//----------------------------------------------------------------------------
// Draw on Screen
//----------------------------------------------------------------------------
void
paintOnScreen()
{
glBindVertexArray(vertexID[1]);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
}
void
display(void) //Display to screen
{
//1.Clear the window
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
glEnable(GL_CULL_FACE);
//2.Translations/Rotations/Projections etc..
glViewport(0, 0, 300, 300);
//3.Draw Objects
paintOnScreen();
glBindVertexArray(0);
//3.Force OpenGL to render
glFlush();
}
void
reshape(int width, int height)
{
glViewport(0, 0, width, height);
//aspect = GLfloat(width)/height;
}
void
keyboard(unsigned char key, int x, int y)
{
switch (key) {
case 033: //ESC
exit(EXIT_SUCCESS);
break;
}
}
//----------------------------------------------------------------------------
int
main(int argc, char **argv)
{
// Initialize glut library
glutInit(&argc, argv);
// Create the window
glutInitDisplayMode(GLUT_RGBA);
glutInitWindowSize(300, 300);
glutInitWindowPosition(300, 200);
glutCreateWindow("Test");
// Initialize glew library
glewInit();
// Your own initialization
init();
// Set callback functions
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutKeyboardFunc(keyboard);
// Start the main loop
glutMainLoop();
return 0;
}
and my fragment shader:
#version 150
in vec2 texCoord;
out vec4 fColor;
uniform sampler2D texture;
void main()
{
fColor = texture2D( texture, texCoord );
}
and my vertex shader:
#version 150
in vec4 vPosition;
in vec2 vTexCoord;
out vec2 texCoord;
void main()
{
texCoord = vTexCoord;
gl_Position = vPosition;
}

Answer 1

You do not specify the texture coords correctly. You define an tex_coords array, but this data is never copied to a VBO (or referenced in the code at all). You set up the vTexCoord attribute pointer to point to the place in the VBO where you copied your colors2 data array, which is all 1.0, so you are constantly accessing the very last texel.