render.cc

void Render_DrawTileMap(dv2 position, i32 *tile_data, i32 world_width, i32 world_height, TileMap tile_map) {
	GLuint texture_id = tile_map.image.id;
	GLint program_id = tile_draw_shader.id;

	f64 tile_scale_x = 1.0 / (f64)tile_map.image.width * (f64)tile_map.width;
	f64 tile_scale_y = 1.0 / (f64)tile_map.image.height * (f64)tile_map.height;
	f64 size_x = 1.0 * meters_to_pixels;
	f64 size_y = 1.0 * meters_to_pixels;

	glUseProgram(program_id);

	glEnableVertexAttribArray(0);
	glEnableVertexAttribArray(1);

	glBindBuffer(GL_ARRAY_BUFFER, rectangle_vertex_buffer_object);
	glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(f32), (void *)0);
	glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(f32), (void *)(2 * sizeof(f32)));

	GLint InputTextureUniform = glGetUniformLocation(program_id, "Texture");
	GLint tile_position_uniform = glGetUniformLocation(program_id, "TilePosition");
	GLint tile_scale_uniform = glGetUniformLocation(program_id, "TileScale");
	GLint position_uniform = glGetUniformLocation(program_id, "Position");
	GLint size_uniform = glGetUniformLocation(program_id, "Size");
	GLint mvp_uniform = glGetUniformLocation(program_id, "MVP");

	for (i32 y = 0; y < world_height; ++y) {
		for (i32 x = 0; x < world_width; ++x) {
			i32 tile = tile_data[x + (y * world_width)];
			u16 t_x = (tile >> 16) & 0xFFFF;
			u16 t_y = tile & 0xFFFF;
			if (t_x != 0xFFFF && t_y != 0xFFFF) {
				glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
				glActiveTexture(GL_TEXTURE0);
				glBindTexture(GL_TEXTURE_2D, texture_id);
				glUniform1i(InputTextureUniform, GL_TEXTURE0);
				glUniform2f(tile_position_uniform, tile_scale_x * t_x, tile_scale_y * t_y);
				glUniform2f(tile_scale_uniform, (GLfloat)tile_scale_x, (GLfloat)tile_scale_y);
				f64 position_x = world_render_position.x + (x * meters_to_pixels) - size_x * 0.5;
				f64 position_y = world_render_position.y + (y * meters_to_pixels) - size_y * 0.5;
				glUniform2f(position_uniform, (GLfloat)position_x, (GLfloat)position_y);
				glUniform2f(size_uniform, (GLfloat)size_y, (GLfloat)size_x);
				glUniformMatrix4fv(mvp_uniform, 1, GL_FALSE, glm::value_ptr(mvp_matrix));

				glDrawArrays(GL_TRIANGLES, 0, 6);
			}
		}
	}

	glDisableVertexAttribArray(0);
	glDisableVertexAttribArray(1);
}