diff options
Diffstat (limited to 'gl.c')
| -rw-r--r-- | gl.c | 20 |
1 files changed, 6 insertions, 14 deletions
@@ -243,14 +243,17 @@ static GLSimpleTriangle *gl_geometry_triangles; static GLuint gl_geometry_program; static GLuint gl_geometry_v_pos; static GLuint gl_geometry_v_color; +static GLint gl_geometry_u_window_size; static GLuint gl_geometry_vbo, gl_geometry_vao; static void gl_geometry_init(void) { char const *vshader_code = "attribute vec2 v_pos;\n\ attribute vec4 v_color;\n\ + uniform vec2 u_window_size;\n\ OUT vec4 color;\n\ void main() {\n\ - gl_Position = vec4(v_pos, 0.0, 1.0);\n\ + vec2 p = v_pos * (2.0 / u_window_size);\n\ + gl_Position = vec4(p.x - 1.0, 1.0 - p.y, 0.0, 1.0);\n\ color = v_color;\n\ }\n\ "; @@ -263,6 +266,7 @@ static void gl_geometry_init(void) { gl_geometry_program = gl_compile_and_link_shaders(NULL, vshader_code, fshader_code); gl_geometry_v_pos = gl_attrib_loc(gl_geometry_program, "v_pos"); gl_geometry_v_color = gl_attrib_loc(gl_geometry_program, "v_color"); + gl_geometry_u_window_size = gl_uniform_loc(gl_geometry_program, "u_window_size"); glGenBuffers(1, &gl_geometry_vbo); if (gl_version_major >= 3) @@ -271,11 +275,6 @@ static void gl_geometry_init(void) { static float gl_window_width, gl_window_height; -static void gl_convert_to_ndc(v2 *pos) { - pos->x = pos->x / gl_window_width * 2.0f - 1.0f; - pos->y = 1.0f - pos->y / gl_window_height * 2.0f; -} - static void gl_geometry_rect(Rect r, u32 color_rgba) { v4 color = rgba_u32_to_v4(color_rgba); @@ -313,14 +312,6 @@ static void gl_geometry_draw(void) { size_t ntriangles = arr_len(gl_geometry_triangles); if (ntriangles == 0) return; - - // convert coordinates to NDC - for (size_t i = 0; i < ntriangles; ++i) { - GLSimpleTriangle *triangle = &gl_geometry_triangles[i]; - gl_convert_to_ndc(&triangle->v1.pos); - gl_convert_to_ndc(&triangle->v2.pos); - gl_convert_to_ndc(&triangle->v3.pos); - } if (gl_version_major >= 3) glBindVertexArray(gl_geometry_vao); @@ -333,6 +324,7 @@ static void gl_geometry_draw(void) { glEnableVertexAttribArray(gl_geometry_v_color); glUseProgram(gl_geometry_program); + glUniform2f(gl_geometry_u_window_size, gl_window_width, gl_window_height); glDrawArrays(GL_TRIANGLES, 0, (GLsizei)(3 * ntriangles)); arr_clear(gl_geometry_triangles); |