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shaders.cpp
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shaders.cpp
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#include "shaders.h"
#include "game.h"
void
print_gl_error(GLenum error_code)
{
switch (error_code)
{
case (GL_INVALID_ENUM):
{
printf("OpenGL error: GL_INVALID_ENUM\n");
} break;
case (GL_INVALID_VALUE):
{
printf("OpenGL error: GL_INVALID_VALUE\n");
} break;
case (GL_INVALID_OPERATION):
{
printf("OpenGL error: GL_INVALID_OPERATION\n");
} break;
case (GL_STACK_OVERFLOW):
{
printf("OpenGL error: GL_STACK_OVERFLOW\n");
} break;
case (GL_STACK_UNDERFLOW):
{
printf("OpenGL error: GL_STACK_UNDERFLOW\n");
} break;
case (GL_OUT_OF_MEMORY):
{
printf("OpenGL error: GL_OUT_OF_MEMORY\n");
} break;
case (GL_INVALID_FRAMEBUFFER_OPERATION):
{
printf("OpenGL error: GL_INVALID_FRAMEBUFFER_OPERATION\n");
} break;
case (GL_TABLE_TOO_LARGE):
{
printf("OpenGL error: GL_TABLE_TOO_LARGE\n");
}
}
}
void
print_gl_errors()
{
GLenum error = glGetError();
while (error != GL_NO_ERROR)
{
print_gl_error(error);
error = glGetError();
}
}
bool
compile_shader(const char shader_source[], int size, GLenum shader_type, GLuint *shader)
{
bool success = true;
*shader = glCreateShader(shader_type);
glShaderSource(*shader, 1, &shader_source, &size);
glCompileShader(*shader);
GLint compile_success = 0;
glGetShaderiv(*shader, GL_COMPILE_STATUS, &compile_success);
if (!compile_success)
{
GLint log_size = 0;
glGetShaderiv(*shader, GL_INFO_LOG_LENGTH, &log_size);
GLchar *log = (GLchar *)malloc(sizeof(GLchar) * log_size);
glGetShaderInfoLog(*shader, log_size, NULL, log);
printf("Shader compile error:\n%s\n", log);
free(log);
glDeleteShader(*shader);
*shader = 0;
success = false;
}
return success;
}
bool
load_shader(const char filename[], GLenum shader_type, GLuint *shader)
{
bool success = true;
*shader = 0;
File file;
if (open_file(filename, &file))
{
success = compile_shader(file.text, file.size, shader_type, shader);
}
else
{
success = false;
}
return success;
}
bool
create_shader_program(const char *filenames[], GLenum types[], int size, GLuint *shader_program)
{
bool success = true;
*shader_program = glCreateProgram();
for (int i = 0; i < size; ++i)
{
GLuint shader;
bool shader_success = load_shader(filenames[i], types[i], &shader);
if (shader_success == 0)
{
success = false;
break;
}
glAttachShader(*shader_program, shader);
}
if (success)
{
glLinkProgram(*shader_program);
GLint is_linked = 0;
glGetProgramiv(*shader_program, GL_LINK_STATUS, &is_linked);
if (is_linked == GL_FALSE)
{
GLint log_size = 0;
glGetProgramiv(*shader_program, GL_INFO_LOG_LENGTH, &log_size);
GLchar *log = (GLchar *)malloc(sizeof(GLchar) * log_size);
glGetProgramInfoLog(*shader_program, log_size, NULL, log);
printf("Shader link error:\n%s\n", log);
free(log);
glDeleteProgram(*shader_program);
success = false;
}
}
return success;
}
GLuint
create_buffer()
{
GLuint result;
int n_buffers = 1;
glGenBuffers(n_buffers, &result);
return result;
}
void
setup_vao(GLuint *vao)
{
glGenVertexArrays(1, vao);
glBindVertexArray(*vao);
}
void
setup_vertex_vbo_ibo(GLuint *vertex_vbo, Vertex *vertices, int n_vertices,
GLuint *vertex_ibo, GLushort *indices, int n_indices)
{
// Vertex VBO
glGenBuffers(1, vertex_vbo);
glBindBuffer(GL_ARRAY_BUFFER, *vertex_vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(Vertex) * n_vertices, vertices, GL_STATIC_DRAW);
GLuint attribute_pos = 0;
glVertexAttribPointer(attribute_pos, sizeof(vec3)/sizeof(float), GL_FLOAT, GL_FALSE, sizeof(Vertex), (void *)offsetof(Vertex, pos));
glEnableVertexAttribArray(attribute_pos);
// Vertex IBO
glGenBuffers(1, vertex_ibo);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, *vertex_ibo);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(GLushort) * n_indices, indices, GL_STATIC_DRAW);
}
void
setup_block_instances_vbo(GLuint *block_instance_vbo, Block *block_instances, int n_block_instances)
{
glGenBuffers(1, block_instance_vbo);
glBindBuffer(GL_ARRAY_BUFFER, *block_instance_vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(Block) * n_block_instances, block_instances, GL_STATIC_DRAW);
GLuint attribute_block_instance_type = 3;
glEnableVertexAttribArray(attribute_block_instance_type);
glVertexAttribPointer(attribute_block_instance_type, sizeof(vec3)/sizeof(float), GL_FLOAT, GL_FALSE, sizeof(Block), (void *)offsetof(Block, type));
glVertexAttribDivisor(attribute_block_instance_type, 1);
// Max attribute size is 4, so have to do mat4 as 4 vec4s
GLuint attribute_block_instance_transform = 4;
int transform_start = offsetof(Block, transformation_matrix);
glEnableVertexAttribArray(attribute_block_instance_transform+0);
glVertexAttribPointer(attribute_block_instance_transform+0, sizeof(vec4)/sizeof(float), GL_FLOAT, GL_FALSE, sizeof(Block), (void *)(transform_start + sizeof(vec4)*0));
glEnableVertexAttribArray(attribute_block_instance_transform+1);
glVertexAttribPointer(attribute_block_instance_transform+1, sizeof(vec4)/sizeof(float), GL_FLOAT, GL_FALSE, sizeof(Block), (void *)(transform_start + sizeof(vec4)*1));
glEnableVertexAttribArray(attribute_block_instance_transform+2);
glVertexAttribPointer(attribute_block_instance_transform+2, sizeof(vec4)/sizeof(float), GL_FLOAT, GL_FALSE, sizeof(Block), (void *)(transform_start + sizeof(vec4)*2));
glEnableVertexAttribArray(attribute_block_instance_transform+3);
glVertexAttribPointer(attribute_block_instance_transform+3, sizeof(vec4)/sizeof(float), GL_FLOAT, GL_FALSE, sizeof(Block), (void *)(transform_start + sizeof(vec4)*3));
glVertexAttribDivisor(attribute_block_instance_transform+0, 1);
glVertexAttribDivisor(attribute_block_instance_transform+1, 1);
glVertexAttribDivisor(attribute_block_instance_transform+2, 1);
glVertexAttribDivisor(attribute_block_instance_transform+3, 1);
}
void
update_block_instance(GLuint block_instance_vbo, int block_instance_n, Block *instance)
{
glBindBuffer(GL_ARRAY_BUFFER, block_instance_vbo);
glBufferSubData(GL_ARRAY_BUFFER, sizeof(Block)*block_instance_n, sizeof(Block), instance);
glBindBuffer(GL_ARRAY_BUFFER, 0);
}
bool
get_uniform_locations(Uniforms *uniforms, GLuint shader_program)
{
bool success = true;
uniforms->uniform_mat4_world_transform = glGetUniformLocation(shader_program, "world_transform");
if (uniforms->uniform_mat4_world_transform == -1)
{
printf("Failed to find uniform mat4 world_transform");
success &= false;
}
uniforms->uniform_vec3_block_type_colours = glGetUniformLocation(shader_program, "block_type_colours");
if (uniforms->uniform_vec3_block_type_colours == -1)
{
printf("Failed to find uniform vec3 block_type_colours");
success &= false;
}
return success;
}