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#include "glgfx.h"
//buffer handles are the ints that gl returns
//buffer data is the data you bind to opengl
GLuint vbhandler; //vertex buffer handle
GLuint ebhandler;
GLuint texhandlers[2];
//handlers for the perspective transforms
GLint projhandler;
GLint tranhandler;
GLint rothandler;
GLint camhandler;
GLint camposhandler;
GLint lightposhandler;
//device coordinates
// ^
// (y+)
// |
//<(x-)-+-(x+)>
// |
// (y-)
// v
//shaders
// z+ is close to screen z- is farther away
GLuint vertexshaderhandle;
GLuint fragmentshaderhandle;
GLuint shaderprogramhandle;
int initglgfx() {
//glew is the library that links all of opengl's fnctions
//for you
glewExperimental = GL_TRUE;
glewInit();
//glEnable (GL_BLEND);
// so we can have transparent polygons
//glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
//culls back face triagnles, which is determined by whether vertexes are clockwise
// or counterclockwise
glEnable(GL_CULL_FACE);
glCullFace(GL_BACK);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
GLuint glnum;
glGenBuffers(1, &glnum);
printf("%u\n",glnum);
//vertex data load of the box model
/* float vertexdata[] = {
-0.500000,0.500000,-0.500000, 0.000000,0.000000,-1.000000, 0.500000,0.500000,-0.500000, 0.000000,0.000000,-1.000000, -0.500000,-0.500000,-0.500000, 0.000000,0.000000,-1.000000,
-0.500000,-0.500000,-0.500000, 0.000000,0.000000,-1.000000, 0.500000,0.500000,-0.500000, 0.000000,0.000000,-1.000000, 0.500000,-0.500000,-0.500000, 0.000000,0.000000,-1.000000,
0.500000,0.500000,-0.500000, 1.000000,0.000000,0.000000, 0.500000,0.500000,0.500000, 1.000000,0.000000,0.000000, 0.500000,-0.500000,-0.500000, 1.000000,0.000000,0.000000,
0.500000,-0.500000,-0.500000, 1.000000,0.000000,0.000000, 0.500000,0.500000,0.500000, 1.000000,0.000000,0.000000, 0.500000,-0.500000,0.500000, 1.000000,0.000000,0.000000,
0.500000,0.500000,0.500000, 0.000000,0.000000,1.000000, -0.500000,0.500000,0.500000, 0.000000,0.000000,1.000000, 0.500000,-0.500000,0.500000, 0.000000,0.000000,1.000000,
-0.500000,0.500000,0.500000, 0.000000,0.000000,1.000000, -0.500000,-0.500000,0.500000, 0.000000,0.000000,1.000000, 0.500000,-0.500000,0.500000, 0.000000,0.000000,1.000000,
-0.500000,0.500000,0.500000, -1.000000,0.000000,0.000000, -0.500000,0.500000,-0.500000, -1.000000,0.000000,0.000000, -0.500000,-0.500000,0.500000, -1.000000,0.000000,0.000000,
-0.500000,0.500000,-0.500000, -1.000000,0.000000,0.000000, -0.500000,-0.500000,-0.500000, -1.000000,0.000000,0.000000, -0.500000,-0.500000,0.500000, -1.000000,0.000000,0.000000,
-0.500000,-0.500000,-0.500000, 0.000000,-1.000000,0.000000, 0.500000,-0.500000,0.500000, 0.000000,-1.000000,0.000000, -0.500000,-0.500000,0.500000, 0.000000,-1.000000,0.000000,
0.500000,-0.500000,-0.500000, 0.000000,-1.000000,0.000000, 0.500000,-0.500000,0.500000, 0.000000,-1.000000,0.000000, -0.500000,-0.500000,-0.500000, 0.000000,-1.000000,0.000000,
-0.500000,0.500000,-0.500000, 0.000000,1.000000,0.000000, -0.500000,0.500000,0.500000, 0.000000,1.000000,0.000000, 0.500000,0.500000,0.500000, 0.000000,1.000000,0.000000,
0.500000,0.500000,0.500000, 0.000000,1.000000,0.000000, 0.500000,0.500000,-0.500000, 0.000000,1.000000,0.000000, -0.500000,0.500000,-0.500000, 0.000000,1.000000,0.000000,
};*/
float vertexdata[] = {
-0.500000,0.500000,-0.500000, 0.000000,0.000000,-1.000000, 0.000000,1.000000,0.000000, 0.500000,0.500000,-0.500000, 0.000000,0.000000,-1.000000, 1.000000,1.000000,0.000000, -0.500000,-0.500000,-0.500000, 0.000000,0.000000,-1.000000, 0.000000,0.000000,0.000000,
-0.500000,-0.500000,-0.500000, 0.000000,0.000000,-1.000000, 0.000000,0.000000,0.000000, 0.500000,0.500000,-0.500000, 0.000000,0.000000,-1.000000, 1.000000,1.000000,0.000000, 0.500000,-0.500000,-0.500000, 0.000000,0.000000,-1.000000, 1.000000,0.000000,0.000000,
0.500000,0.500000,-0.500000, 1.000000,0.000000,0.000000, 0.000000,1.000000,0.000000, 0.500000,0.500000,0.500000, 1.000000,0.000000,0.000000, 1.000000,1.000000,0.000000, 0.500000,-0.500000,-0.500000, 1.000000,0.000000,0.000000, 0.000000,0.000000,0.000000,
0.500000,-0.500000,-0.500000, 1.000000,0.000000,0.000000, 0.000000,0.000000,0.000000, 0.500000,0.500000,0.500000, 1.000000,0.000000,0.000000, 1.000000,1.000000,0.000000, 0.500000,-0.500000,0.500000, 1.000000,0.000000,0.000000, 1.000000,0.000000,0.000000,
0.500000,0.500000,0.500000, 0.000000,0.000000,1.000000, 0.000000,1.000000,0.000000, -0.500000,0.500000,0.500000, 0.000000,0.000000,1.000000, 1.000000,1.000000,0.000000, 0.500000,-0.500000,0.500000, 0.000000,0.000000,1.000000, 0.000000,0.000000,0.000000,
-0.500000,0.500000,0.500000, 0.000000,0.000000,1.000000, 1.000000,1.000000,0.000000, -0.500000,-0.500000,0.500000, 0.000000,0.000000,1.000000, 1.000000,0.000000,0.000000, 0.500000,-0.500000,0.500000, 0.000000,0.000000,1.000000, 0.000000,0.000000,0.000000,
-0.500000,0.500000,0.500000, -1.000000,0.000000,0.000000, 0.000000,1.000000,0.000000, -0.500000,0.500000,-0.500000, -1.000000,0.000000,0.000000, 1.000000,1.000000,0.000000, -0.500000,-0.500000,0.500000, -1.000000,0.000000,0.000000, 0.000000,0.000000,0.000000,
-0.500000,0.500000,-0.500000, -1.000000,0.000000,0.000000, 1.000000,1.000000,0.000000, -0.500000,-0.500000,-0.500000, -1.000000,0.000000,0.000000, 1.000000,0.000000,0.000000, -0.500000,-0.500000,0.500000, -1.000000,0.000000,0.000000, 0.000000,0.000000,0.000000,
-0.500000,-0.500000,-0.500000, 0.000000,-1.000000,0.000000, 0.000000,0.000000,0.000000, 0.500000,-0.500000,0.500000, 0.000000,-1.000000,0.000000, 1.000000,1.000000,0.000000, -0.500000,-0.500000,0.500000, 0.000000,-1.000000,0.000000, 0.000000,1.000000,0.000000,
0.500000,-0.500000,-0.500000, 0.000000,-1.000000,0.000000, 1.000000,0.000000,0.000000, 0.500000,-0.500000,0.500000, 0.000000,-1.000000,0.000000, 1.000000,1.000000,0.000000, -0.500000,-0.500000,-0.500000, 0.000000,-1.000000,0.000000, 0.000000,0.000000,0.000000,
-0.500000,0.500000,-0.500000, 0.000000,1.000000,0.000000, 0.000000,0.000000,0.000000, -0.500000,0.500000,0.500000, 0.000000,1.000000,0.000000, 1.000000,0.000000,0.000000, 0.500000,0.500000,0.500000, 0.000000,1.000000,0.000000, 1.000000,1.000000,0.000000,
0.500000,0.500000,0.500000, 0.000000,1.000000,0.000000, 1.000000,1.000000,0.000000, 0.500000,0.500000,-0.500000, 0.000000,1.000000,0.000000, 0.000000,1.000000,0.000000, -0.500000,0.500000,-0.500000, 0.000000,1.000000,0.000000, 0.000000,0.000000,0.000000,
};
/* float vertexdata[] = {
-0.5, 0.5, -.5, // x y z
0.5, 0.5, -.5,
0.5, -0.5, -.5,
-0.5, -0.5, -.5,
-0.5, 0.5, 0.5, // x y z
0.5, 0.5, 0.5,
0.5, -0.5, 0.5,
-0.5, -0.5, 0.5,
//normal positions
1.0, 0.0, 0.0,
-1.0, 0.0, 0.0,
0.0, 1.0, 0.0,
0.0, -1.0, 0.0,
0.0, 0.0, 1.0,
0.0, 0.0, -1.0,
};
*/
//polygons of the box mode based on the vertex data.
//they must be clockwise from the front so that they are culled when not
//seen
/* GLuint elementdata[] = {
0,12, 1,12, 3,12,
3,12, 1,12, 2,12,
1,8, 5,8, 2,8,
2,8, 5,8, 6,8,
5,13, 4,13, 6,13,
4,13, 7,13, 6,13,
4,9, 0,9, 7,9,
0,9, 3,9, 7,9,
3,11, 6,11, 7,11,
2,11, 6,11, 3,11,
0,10, 4,10, 5,10,
5,10, 1,10, 0,10,
};
*/
GLuint elementdata[] = {
0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35
};
//binds to the element buffer
glGenBuffers(1,&vbhandler);
glBindBuffer(GL_ARRAY_BUFFER,vbhandler);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertexdata), vertexdata, GL_DYNAMIC_DRAW);
glGenBuffers(1,&ebhandler);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,ebhandler);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(elementdata), elementdata, GL_DYNAMIC_DRAW);
//loads textures
glGenTextures(2, texhandlers);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texhandlers[0]);
glgfxloadtexture("textures/tex.bmp");
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, texhandlers[1]);
glgfxloadtexture("textures/elev.bmp");
//loads the shaders
genshaders();
glUniform1i(glGetUniformLocation(shaderprogramhandle, "tex"), 0);
glUniform1i(glGetUniformLocation(shaderprogramhandle, "elev"), 1);
}
//loads shaders and models
int genshaders() {
//flowchart
//vertex shader receives raw vertex data, outputs that data transformed in 3d space(camera), that data is passed to
//geometry shader, which is where we will add normal vector for
//light calculations // also where we make the volumetric information
//all these are rasterized, and blended for every pixel value
//then passed to fragment shader
//which is where we do the light calculations
//tests and blending(multiple buffers?)
//reads from files
//debug printout
//printf(readfile("vertexshader.glsl").c_str());
std::string vertexshadersource = readfile("vertexshader.glsl").c_str();
std::string fragmentshadersource = readfile("fragmentshader.glsl").c_str();
const char * vertexshaderstr = vertexshadersource.c_str();
const char * fragmentshaderstr = fragmentshadersource.c_str();
GLuint vertexshaderhandle = glCreateShader(GL_VERTEX_SHADER);
int vertexshaderlen = vertexshadersource.length();
//length of the source must be specified
glShaderSource(vertexshaderhandle, 1, (&vertexshaderstr), &vertexshaderlen);
glCompileShader(vertexshaderhandle);
//error buffer
char buffer[512];
GLint err;
glGetShaderiv(vertexshaderhandle, GL_COMPILE_STATUS, &err);
if (err == GL_FALSE) {
glGetShaderInfoLog(vertexshaderhandle, 512, NULL, buffer);
printf("error compiling vertex shhader\n");
printf(buffer);
}
GLuint fragmentshaderhandle = glCreateShader(GL_FRAGMENT_SHADER);
int fragmentshaderlen = fragmentshadersource.length();
//the length of the source must be specified
glShaderSource(fragmentshaderhandle, 1, (&fragmentshaderstr), &fragmentshaderlen);
glCompileShader(fragmentshaderhandle);
glGetShaderiv(fragmentshaderhandle, GL_COMPILE_STATUS, &err);
if (err == GL_FALSE) {
glGetShaderInfoLog(fragmentshaderhandle, 512, NULL, buffer);
printf("error compiling fragment shader\n");
printf(buffer);
}
//make the shader program
shaderprogramhandle = glCreateProgram();
glAttachShader(shaderprogramhandle,vertexshaderhandle);
glAttachShader(shaderprogramhandle,fragmentshaderhandle);
//the 0 is which buffer, 0 is the default, 1 will be fore volumetric shading
glBindFragDataLocation(shaderprogramhandle,0,"outpix");
glLinkProgram(shaderprogramhandle);
glUseProgram(shaderprogramhandle);
//vertex data
GLint pos;
pos = glGetAttribLocation(shaderprogramhandle, "position");
//the actual atribute, number of values, type, whether they need to be normalied to -1 1,
//number of bytes between values, offset from beginning in bytes
glVertexAttribPointer(pos, 3, GL_FLOAT, GL_FALSE, 9 * sizeof(float), 0);
glEnableVertexAttribArray(pos);
GLint vnorm;
vnorm = glGetAttribLocation(shaderprogramhandle, "vnormal");
//the actual atribute, number of values, type, whether they need to be normalied to -1 1,
//number of bytes between values, offset from beginning in bytes
glVertexAttribPointer(vnorm, 3, GL_FLOAT, GL_FALSE, 9 * sizeof(float), (void *) (3 * sizeof(float)) );
glEnableVertexAttribArray(vnorm);
GLint texcoord;
texcoord = glGetAttribLocation(shaderprogramhandle, "texcoord");
//the actual atribute, number of values, type, whether they need to be normalied to -1 1,
//number of bytes between values, offset from beginning in bytes
glVertexAttribPointer(texcoord, 3, GL_FLOAT, GL_FALSE, 9 * sizeof(float), (void *) (6 * sizeof(float)) );
glEnableVertexAttribArray(texcoord);
//getting uniform handler
projhandler = glGetUniformLocation(shaderprogramhandle, "proj");
camhandler = glGetUniformLocation(shaderprogramhandle, "cam");
tranhandler = glGetUniformLocation(shaderprogramhandle, "tran");
rothandler = glGetUniformLocation(shaderprogramhandle, "rot");
lightposhandler = glGetUniformLocation(shaderprogramhandle, "lightpos");
camposhandler = glGetUniformLocation(shaderprogramhandle, "campos");
}
//opens a filebuffer stream and reads every char
std::string readfile(char const * filename) {
std::ifstream filebuffer;
std::string line;
std::string rstr;
rstr = "";
char c;
filebuffer.open(filename);
if (!filebuffer.is_open()) {
printf("error reading file");
}
while (filebuffer.get(c)) {
rstr = rstr + c;
}
filebuffer.close();
return rstr;
}
int setcam (float cpx, float cpy, float cpz, float clx, float cly, float clz, float cux, float cuy, float cuz) {
//lookat eye position of camera, center center of screen, up up direction
//glm::mat4 cam = glm::lookAt(glm::vec3(0,0,1), glm::vec3(0,0,0),glm::vec3(0,1,0));
glm::mat4 cam = glm::lookAt(glm::vec3(cpx, cpy, cpz), glm::vec3(clx, cly, clz), glm::vec3(cux, cuy, cuz));
glUniformMatrix4fv(camhandler, 1, GL_FALSE, glm::value_ptr(cam));
glUniform3fv(camposhandler, 1, glm::value_ptr(glm::vec3(cpx,cpy,cpz)));
return 0;
}
int setlight (float x, float y, float z) {
glUniform3fv(camposhandler, 1, glm::value_ptr(glm::vec3(x,y,z)));
return 0;
}
//draws the model, setting perspective transform and position transform
//done with magic numbers for now for testing purposes
int drawmodel(float x, float y, float z, float xr, float yr, float zr, float s) {
// the transformation matrix = rotation matrix of object * scaling matrix * translaton matrix representing difference in camera and object location * -rotation matrix of the camera * perspective transform
//order of application ir right to left
//fov, aspect ratio, size of near and far planes distance
glm::mat4 proj = glm::perspective(glm::radians(45.0f), (float)maxx/(float)maxy, 0.1f, 100.0f);
glUniformMatrix4fv(projhandler, 1, GL_FALSE, glm::value_ptr(proj));
//a valid tranlation matrix showing the colun first conventions of glm::mat4
//tran = glm::mat4(
// glm::vec4(1.0f,0.0f,0.0f,0.0f), //x transform is the one on the last column
// glm::vec4(0.0f,1.0f,0.0f,0.0f), //y
// glm::vec4(0.0f,0.0f,1.0f,0.0f), // z
// glm::vec4(0.0f,0.0f,0.5f,1.0f) //w just make it 1
//);
//the translation matrix, matrixes added last are applied first
glm::mat4 tran;
tran = glm::scale(tran, glm::vec3(s,s,s));
tran = glm::translate(tran, glm::vec3(x,y,z));
tran = glm::rotate(tran,glm::radians(xr),glm::vec3(1,0,0)); // axis of rotation x y z
tran = glm::rotate(tran,glm::radians(yr),glm::vec3(0,1,0));
tran = glm::rotate(tran,glm::radians(zr),glm::vec3(0,0,1));
glm::mat4 rot;
rot = glm::rotate(rot,glm::radians(xr),glm::vec3(1,0,0)); // axis of rotation x y z
rot = glm::rotate(rot,glm::radians(yr),glm::vec3(0,1,0));
rot = glm::rotate(rot,glm::radians(zr),glm::vec3(0,0,1));
//deprecated debug stuff
//printf("translated vector x%f\n",(tran * glm::vec4(1.0f,0.0f,0.0f,1.0f)).x);
//printf("translated vector y%f\n",(tran * glm::vec4(0.0f,1.0f,0.0f,1.0f)).y);
//printf("translated vector z%f\n",(tran * glm::vec4(0.0f,0.0f,1.0f,1.0f)).z);
//printf("translated vector x%f\n",(rot * glm::vec4(1.0f,0.0f,0.0f,1.0f)).x);
//printf("translated vector y%f\n",(rot * glm::vec4(0.0f,1.0f,0.0f,1.0f)).y);
//printf("translated vector z%f\n",(rot * glm::vec4(0.0f,0.0f,1.0f,1.0f)).z);
//loads the transaltion stuff
glUniformMatrix4fv(tranhandler, 1, GL_FALSE, glm::value_ptr(tran));
glUniformMatrix4fv(rothandler, 1, GL_FALSE, glm::value_ptr(rot));
//glDrawElements(GL_TRIANGLES, 36, GL_UNSIGNED_INT, 0);
glDrawArrays(GL_TRIANGLES,0,36);
}
int quitglgfx() {
}
int clearglgfx() {
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
return 0;
}
int glgfxloadtexture (const char * file) {
SDL_Surface * tsp;
tsp = SDL_LoadBMP(file);
//we're just gonna forget their handlers since loading texture data is a
//one time thing anyways
//texture to bind to, detail,format,
printf("num of pixels\n %d \n", tsp->format->BitsPerPixel); //32 bits per pixel
printf("Rmask\n %04x \n", tsp->format->Rmask); // ff000000
printf("Gmask\n %04x \n", tsp->format->Gmask); // 00ff0000
printf("Bmask\n %04x \n", tsp->format->Bmask); // 0000ff00
printf("Amask\n %04x \n", tsp->format->Amask); // 000000ff
tsp = SDL_ConvertSurfaceFormat(tsp, SDL_PIXELFORMAT_RGBA32, 0);
//int w;
//int h;
//int c;
//unsigned char * data =SOIL_load_image(file, &w, &h,&c, SOIL_LOAD_BMP);
//printf("w%d\n",h);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, tsp->w, tsp->h, 0, GL_RGBA, GL_UNSIGNED_BYTE,(void *) tsp->pixels);
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
//drawimg(0,0,100,100,file);
SDL_FreeSurface(tsp);
}
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