MapTex.cpp

#include "MapTex.h"
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <fstream>
#include <sstream>

GLenum types[6] = { GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, GL_TEXTURE_CUBE_MAP_POSITIVE_Z, GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, GL_TEXTURE_CUBE_MAP_POSITIVE_Y, GL_TEXTURE_CUBE_MAP_NEGATIVE_X, GL_TEXTURE_CUBE_MAP_POSITIVE_X };



/** Load a ppm file from disk.
@input filename The location of the PPM file.  If the file is not found, an error message
will be printed and this function will return 0
@input width This will be modified to contain the width of the loaded image, or 0 if file not found
@input height This will be modified to contain the height of the loaded image, or 0 if file not found
@return Returns the RGB pixel data as interleaved unsigned chars (R0 G0 B0 R1 G1 B1 R2 G2 B2 .... etc) or 0 if an error ocured
**/
unsigned char* loadPPM(const char* filename, int& width, int& height)
{
	const int BUFSIZE = 128;
	FILE* fp;
	unsigned int read;
	unsigned char* rawData;
	char buf[3][BUFSIZE];
	char* retval_fgets;
	size_t retval_sscanf;

	if ((fp = fopen(filename, "rb")) == NULL)
	{
		std::cerr << "error reading ppm file, could not locate " << filename << std::endl;
		width = 0;
		height = 0;
		return NULL;
	}

	// Read magic number:
	retval_fgets = fgets(buf[0], BUFSIZE, fp);

	// Read width and height:
	do
	{
		retval_fgets = fgets(buf[0], BUFSIZE, fp);
	} while (buf[0][0] == '#');
	retval_sscanf = sscanf(buf[0], "%s %s", buf[1], buf[2]);
	width = atoi(buf[1]);
	height = atoi(buf[2]);

	// Read maxval:
	do
	{
		retval_fgets = fgets(buf[0], BUFSIZE, fp);
	} while (buf[0][0] == '#');

	// Read image data:
	rawData = new unsigned char[width * height * 3];
	read = fread(rawData, width * height * 3, 1, fp);
	fclose(fp);
	if (read != 1)
	{
		std::cerr << "error parsing ppm file, incomplete data" << std::endl;
		delete[] rawData;
		width = 0;
		height = 0;
		return NULL;
	}

	return rawData;
}




bool MapTex::load()
{
	glGenTextures(1, &m_textureObj);
	glBindTexture(GL_TEXTURE_CUBE_MAP, m_textureObj);



	GLuint texture[1];     // storage for one texture
	int twidth, theight;   // texture width/height [pixels]
	unsigned char* tdata;  // texture pixel data

	
	for (unsigned int i = 0; i < 6; i++) {
		// Load image file
		tdata = loadPPM("image.ppm", twidth, theight);
		if (tdata == NULL) return false;
		glTexImage2D(types[i], 0, GL_RGB, twidth, theight, 0, GL_RGBA,
			GL_UNSIGNED_BYTE, tdata);
	}

	glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
	glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);

	return true;
}

float points[] = {
	-10.0f, 10.0f, -10.0f,
	-10.0f, -10.0f, -10.0f,
	10.0f, -10.0f, -10.0f,
	10.0f, -10.0f, -10.0f,
	10.0f, 10.0f, -10.0f,
	-10.0f, 10.0f, -10.0f,

	-10.0f, -10.0f, 10.0f,
	-10.0f, -10.0f, -10.0f,
	-10.0f, 10.0f, -10.0f,
	-10.0f, 10.0f, -10.0f,
	-10.0f, 10.0f, 10.0f,
	-10.0f, -10.0f, 10.0f,

	10.0f, -10.0f, -10.0f,
	10.0f, -10.0f, 10.0f,
	10.0f, 10.0f, 10.0f,
	10.0f, 10.0f, 10.0f,
	10.0f, 10.0f, -10.0f,
	10.0f, -10.0f, -10.0f,

	-10.0f, -10.0f, 10.0f,
	-10.0f, 10.0f, 10.0f,
	10.0f, 10.0f, 10.0f,
	10.0f, 10.0f, 10.0f,
	10.0f, -10.0f, 10.0f,
	-10.0f, -10.0f, 10.0f,

	-10.0f, 10.0f, -10.0f,
	10.0f, 10.0f, -10.0f,
	10.0f, 10.0f, 10.0f,
	10.0f, 10.0f, 10.0f,
	-10.0f, 10.0f, 10.0f,
	-10.0f, 10.0f, -10.0f,

	-10.0f, -10.0f, -10.0f,
	-10.0f, -10.0f, 10.0f,
	10.0f, -10.0f, -10.0f,
	10.0f, -10.0f, -10.0f,
	-10.0f, -10.0f, 10.0f,
	10.0f, -10.0f, 10.0f
};

// load image file into texture object
void MapTex::loadTexture()
{
	GLuint vbo;
	glGenBuffers(1, &vbo);
	glBindBuffer(GL_ARRAY_BUFFER, vbo);
	glBufferData(GL_ARRAY_BUFFER, 3 * 36 * sizeof(float), &points, GL_STATIC_DRAW);

	GLuint vao;
	glGenVertexArrays(1, &vao);
	glBindVertexArray(vao);
	glEnableVertexAttribArray(0);
	glBindBuffer(GL_ARRAY_BUFFER, vbo);
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, NULL);

	glActiveTexture(GL_TEXTURE0);
	glGenTextures(1, &m_textureObj);
	glBindTexture(GL_TEXTURE_CUBE_MAP, m_textureObj);


	GLuint texture[1];     // storage for one texture
	int twidth, theight;   // texture width/height [pixels]
	unsigned char* tdata;  // texture pixel data

	// Load image file
	tdata = loadPPM("image.ppm", twidth, theight);
	if (tdata == NULL) return;

	glDepthMask(GL_FALSE);
	//glUseProgram(shader_programme);
	glBindVertexArray(vao);
	glDrawArrays(GL_TRIANGLES, 0, 36);
	glDepthMask(GL_TRUE);


	// Create ID for texture
	glGenTextures(1, &texture[0]);

	// Set this texture to be the one we are working with
	glBindTexture(GL_TEXTURE_2D, texture[0]);

	// Generate the texture
	glTexImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, 0, 3, twidth, theight, 0, GL_RGB, GL_UNSIGNED_BYTE, tdata);
	glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_Z, 0, 3, twidth, theight, 0, GL_RGB, GL_UNSIGNED_BYTE, tdata);
	glTexImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, 0, 3, twidth, theight, 0, GL_RGB, GL_UNSIGNED_BYTE, tdata);
	glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_Y, 0, 3, twidth, theight, 0, GL_RGB, GL_UNSIGNED_BYTE, tdata);
	glTexImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_X, 0, 3, twidth, theight, 0, GL_RGB, GL_UNSIGNED_BYTE, tdata);
	glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X, 0, 3, twidth, theight, 0, GL_RGB, GL_UNSIGNED_BYTE, tdata);

	// Set bi-linear filtering for both minification and magnification
	glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
	glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
}