diff options
Diffstat (limited to 'shaders.cpp')
| -rw-r--r-- | shaders.cpp | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/shaders.cpp b/shaders.cpp new file mode 100644 index 0000000..95c0bac --- /dev/null +++ b/shaders.cpp @@ -0,0 +1,138 @@ +// compile a vertex or fragment shader +static GLuint shader_compile_from_file(GL *gl, char const *filename, GLenum shader_type) { + FILE *fp = fopen(filename, "rb"); + if (fp) { + char code[16384] = {0}; + char log[4096] = {0}; + char const *const_code = code; + fread(code, 1, sizeof code, fp); + GLuint shader = gl->CreateShader(shader_type); + if (shader == 0) { + logln("Couldn't create shader: %u",glGetError()); + } + gl->ShaderSource(shader, 1, &const_code, NULL); + gl->CompileShader(shader); + gl->GetShaderInfoLog(shader, sizeof log - 1, NULL, log); + if (*log) { + logln("Error compiling shader:\n%s", log); + gl->DeleteShader(shader); + return 0; + } + return shader; + } else { + logln("File does not exist: %s.", filename); + return 0; + } +} + +#if DEBUG +static struct timespec shader_get_last_modified(ShaderBase *shader) { + // the last modified time of the shader is whichever of the vertex/fragment shaders was modified last + return timespec_max( + time_last_modified(shader->vertex_filename), + time_last_modified(shader->fragment_filename) + ); +} +#endif + +static GLuint shader_attrib_location(GL *gl, ShaderBase *shader, char const *attrib) { + GLint loc = gl->GetAttribLocation(shader->program, attrib); + if (loc == -1) { + printf("Couldn't find vertex attribute %s.\n", attrib); + return 0; + } + return (GLuint)loc; +} + +static GLint shader_uniform_location(GL *gl, ShaderBase *shader, char const *uniform) { + GLint loc = gl->GetUniformLocation(shader->program, uniform); + if (loc == -1) { + printf("Couldn't find uniform: %s.\n", uniform); + return -1; + } + return loc; +} + +// compile a full shader program +static void shader_load(GL *gl, ShaderBase *shader, char const *vertex_filename, char const *fragment_filename) { +#if DEBUG + str_cpy(shader->vertex_filename, sizeof shader->vertex_filename, vertex_filename); + str_cpy(shader->fragment_filename, sizeof shader->fragment_filename, fragment_filename); + shader->last_modified = shader_get_last_modified(shader); + + if (shader->program) gl->DeleteProgram(shader->program); +#endif + + + GLuint vertex_shader = shader_compile_from_file(gl, vertex_filename, GL_VERTEX_SHADER); + GLuint fragment_shader = shader_compile_from_file(gl, fragment_filename, GL_FRAGMENT_SHADER); + GLuint program = gl->CreateProgram(); + gl->AttachShader(program, vertex_shader); + gl->AttachShader(program, fragment_shader); + gl->LinkProgram(program); + char log[4096] = {0}; + gl->GetProgramInfoLog(program, sizeof log - 1, NULL, log); + if (*log) { + logln("Error linking shader:\n%s", log); + gl->DeleteProgram(program); + program = 0; + } + gl->DeleteShader(vertex_shader); + gl->DeleteShader(fragment_shader); + shader->program = program; + + GLenum err = glGetError(); + if (err) { + logln("Error loading shader %s/%s: %u.", vertex_filename, fragment_filename, err); + } else { + logln("Loaded shader %s/%s as %u.", vertex_filename, fragment_filename, program); + } +} + +static void shader_start_using(GL *gl, ShaderBase *shader) { + gl->UseProgram(shader->program); +} + +static void shader_stop_using(GL *gl) { + gl->UseProgram(0); +} + +#if DEBUG +static bool shader_needs_reloading(ShaderBase *shader) { + return !timespec_eq(shader->last_modified, shader_get_last_modified(shader)); +} +#endif + +static void shader_platform_load(GL *gl, ShaderPlatform *shader) { + ShaderBase *base = &shader->base; + shader_load(gl, base, "assets/platform_v.glsl", "assets/platform_f.glsl"); + shader->vertex_p1 = shader_attrib_location(gl, base, "vertex_p1"); + shader->vertex_p2 = shader_attrib_location(gl, base, "vertex_p2"); + shader->uniform_thickness = shader_uniform_location(gl, base, "thickness"); + shader->uniform_transform = shader_uniform_location(gl, base, "transform"); +} + +static void shader_ball_load(GL *gl, ShaderBall *shader) { + ShaderBase *base = &shader->base; + shader_load(gl, base, "assets/ball_v.glsl", "assets/ball_f.glsl"); + shader->uniform_transform = shader_uniform_location(gl, base, "transform"); + shader->uniform_center = shader_uniform_location(gl, base, "center"); + shader->uniform_radius = shader_uniform_location(gl, base, "radius"); +} + +static void shaders_load(State *state) { + GL *gl = &state->gl; + shader_platform_load(gl, &state->shader_platform); + shader_ball_load(gl, &state->shader_ball); +} + +#if DEBUG +static void shaders_reload_if_necessary(State *state) { + GL *gl = &state->gl; + if (shader_needs_reloading(&state->shader_platform.base)) + shader_platform_load(gl, &state->shader_platform); + if (shader_needs_reloading(&state->shader_ball.base)) + shader_ball_load(gl, &state->shader_ball); +} +#endif + |