GLSL shortcuts

glsl.c

#include GL

#include "glsl.h"

void glsl_setup(glsl_program *program) {
  int gl_program = program->gl_program = glCreateProgram();
  int i;

  for (i = 0; i < program->n_shaders; i++) {
    glsl_shader *shader = &program->shaders[i];

    int gl_shader = glCreateShader(shader->type);
    glShaderSource(gl_shader, 1, &shader->source, 0);
    glCompileShader(gl_shader);
//char buffer[256];
//glGetShaderInfoLog(gl_shader, sizeof(buffer), 0, buffer);
//printf("%s\n", buffer);
    glAttachShader(gl_program, gl_shader);
    glDeleteShader(gl_shader);
  }

  for (i = 0; i < program->n_attribs; i++) {
    glsl_attrib *attrib = &program->attribs[i];

    glBindAttribLocation(gl_program, i, attrib->symbol);
  }

  glLinkProgram(gl_program);

  for (i = 0; i < program->n_uniforms; i++) {
    glsl_uniform *uniform = &program->uniforms[i];

    uniform->location = glGetUniformLocation(gl_program, uniform->symbol);
  }

  glGenBuffers(1, &program->vbo);
  glBindBuffer(GL_ARRAY_BUFFER, program->vbo);
  glBufferData(GL_ARRAY_BUFFER,
    program->vb_n_elements * program->stride * sizeof(GLfloat),
    program->vb, program->vbo_hint);

  glGenBuffers(1, &program->ibo);
  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, program->ibo);
  glBufferData(GL_ELEMENT_ARRAY_BUFFER,
    program->ib_n_elements * sizeof(GLushort),
    program->ib, program->ibo_hint);
}

void glsl_subdata_vb(glsl_program *program) {
  glBindBuffer(GL_ARRAY_BUFFER, program->vbo);
  glBufferSubData(GL_ARRAY_BUFFER,
    0, program->vb_n_elements * program->stride * sizeof(GLfloat),
    program->vb);
}

void glsl_subdata_ib(glsl_program *program) {
  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, program->ibo);
  glBufferSubData(GL_ELEMENT_ARRAY_BUFFER,
    0, program->ib_n_elements * sizeof(GLushort),
    program->ib);
}

void glsl_render(glsl_program *program) {
  int i;

  glBindBuffer(GL_ARRAY_BUFFER, program->vbo);
  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, program->ibo);

  for (i = 0; i < program->n_attribs; i++) {
    glsl_attrib *attrib = &program->attribs[i];
    const GLvoid *pointer = (GLvoid *)(attrib->offset * sizeof(GLfloat));

    glEnableVertexAttribArray(i);
    glVertexAttribPointer(i, attrib->count, GL_FLOAT, GL_FALSE,
      program->stride * sizeof(GLfloat), pointer);
  }

  glDrawElements(GL_TRIANGLES, program->ib_n_elements, GL_UNSIGNED_SHORT, 0);

  for (i = 0; i < program->n_attribs; i++) {
    glDisableVertexAttribArray(i);
  }
}

glsl.h

typedef struct {
  int type;
  const char *source;
} glsl_shader;

typedef struct {
  int offset;
  int count;
  char *symbol;
} glsl_attrib;

typedef struct {
  int location;
  char *symbol;
} glsl_uniform;

typedef struct {
  int gl_program;
  int stride;
  int n_shaders;
  glsl_shader *shaders;
  int n_attribs;
  glsl_attrib *attribs;
  int n_uniforms;
  glsl_uniform *uniforms;
  unsigned int vbo;
  int vb_n_elements;
  float *vb;
  int vbo_hint;
  unsigned int ibo;
  int ib_n_elements;
  unsigned short *ib;
  int ibo_hint;
} glsl_program;

void glsl_setup(glsl_program *program);
void glsl_subdata_ib(glsl_program *program);
void glsl_subdata_vb(glsl_program *program);
void glsl_render(glsl_program *program);