Start work on the graphics program

kitty/gl.h

@@ -338,11 +338,9 @@ add_buffer_to_vao(ssize_t vao_idx, GLenum usage) {
 }
 
 static void
-add_attribute_to_vao(int p, ssize_t vao_idx, const char *name, GLint size, GLenum data_type, GLsizei stride, void *offset, GLuint divisor) {
+add_located_attribute_to_vao(ssize_t vao_idx, GLint aloc, GLint size, GLenum data_type, GLsizei stride, void *offset, GLuint divisor) {
     VAO *vao = vaos + vao_idx;
-    if (!vao->num_buffers) { fatal("You must create a buffer for this attribute first"); return; }
+    if (!vao->num_buffers) fatal("You must create a buffer for this attribute first"); 
-    GLint aloc = attrib_location(p, name);
-    if (aloc == -1) { fatal("No attribute named: %s found in this program", name); return; }
     ssize_t buf = vao->buffers[vao->num_buffers - 1];
     bind_buffer(buf);
     glEnableVertexAttribArray(aloc);
@@ -366,7 +364,14 @@ add_attribute_to_vao(int p, ssize_t vao_idx, const char *name, GLint size, GLenu
         check_gl();
     }
     unbind_buffer(buf);
-    return;
+}
+
+
+static inline void
+add_attribute_to_vao(int p, ssize_t vao_idx, const char *name, GLint size, GLenum data_type, GLsizei stride, void *offset, GLuint divisor) {
+    GLint aloc = attrib_location(p, name);
+    if (aloc == -1) fatal("No attribute named: %s found in this program", name); 
+    add_located_attribute_to_vao(vao_idx, aloc, size, data_type, stride, offset, divisor);
 }
 
 static void

kitty/graphics_fragment.glsl

@@ -0,0 +1,10 @@
+#version 330
+
+uniform sampler2D image;
+
+in vec2 texcoord;
+out vec4 color;
+
+void main() {
+    color = texture2D(image, texcoord);
+}

kitty/graphics_vertex.glsl

@@ -0,0 +1,19 @@
+#version 330
+
+layout(location=8) in vec4 src;
+layout(location=9) in vec4 position;
+out vec2 texcoord;
+
+const uvec2 pos_map[] = uvec2[4](
+    uvec2(1, 0),  // right, top
+    uvec2(1, 1),  // right, bottom
+    uvec2(0, 1),  // left, bottom
+    uvec2(0, 0)   // left, top
+);
+
+
+void main() {
+    uvec2 pos = pos_map[gl_VertexID];
+    gl_Position = vec4(position[pos.x], position[pos.y + uint(2)], 0, 1);
+    texcoord = vec2(src[pos.x], src[pos.y + uint(2)]);
+}

kitty/shaders.c

@@ -7,7 +7,7 @@
 
 #include "gl.h"
 
-enum { CELL_PROGRAM, CELL_BACKGROUND_PROGRAM, CELL_SPECIAL_PROGRAM, CELL_FOREGROUND_PROGRAM, CURSOR_PROGRAM, BORDERS_PROGRAM, NUM_PROGRAMS };
+enum { CELL_PROGRAM, CELL_BACKGROUND_PROGRAM, CELL_SPECIAL_PROGRAM, CELL_FOREGROUND_PROGRAM, CURSOR_PROGRAM, BORDERS_PROGRAM, GRAPHICS_PROGRAM, NUM_PROGRAMS };
 
 // Sprites {{{
 typedef struct {
@@ -175,8 +175,6 @@ destroy_sprite_map() {
 
 // Cell {{{
 
-#define CELL_BUFFERS enum { cell_data_buffer, selection_buffer, uniform_buffer };
-
 typedef struct {
     UniformBlock render_data;
     ArrayInformation color_table;
@@ -195,6 +193,8 @@ init_cell_program() {
     }
 }
 
+#define CELL_BUFFERS enum { cell_data_buffer, selection_buffer, uniform_buffer, graphics_buffer };
+
 static ssize_t
 create_cell_vao() {
     ssize_t vao_idx = create_vao();
@@ -202,17 +202,26 @@ create_cell_vao() {
     add_attribute_to_vao(CELL_PROGRAM, vao_idx, #name, \
             /*size=*/size, /*dtype=*/dtype, /*stride=*/stride, /*offset=*/offset, /*divisor=*/1);
 #define A1(name, size, dtype, offset) A(name, size, dtype, (void*)(offsetof(Cell, offset)), sizeof(Cell))
+#define AL(p, name, size, dtype, offset, stride) { GLint aloc = attrib_location(p, name); if (aloc == -1 ) fatal("No attribute named: %s found in this program", name); add_located_attribute_to_vao(vao_idx, aloc, size, dtype, stride, (void*)offset, 1); }
 
     add_buffer_to_vao(vao_idx, GL_ARRAY_BUFFER);
     A1(sprite_coords, 4, GL_UNSIGNED_SHORT, sprite_x);
     A1(colors, 3, GL_UNSIGNED_INT, fg);
+
     add_buffer_to_vao(vao_idx, GL_ARRAY_BUFFER);
     A(is_selected, 1, GL_FLOAT, NULL, 0);
+
     size_t bufnum = add_buffer_to_vao(vao_idx, GL_UNIFORM_BUFFER);
     alloc_vao_buffer(vao_idx, cell_program_layouts[CELL_PROGRAM].render_data.size, bufnum, GL_STREAM_DRAW);
+
+    add_buffer_to_vao(vao_idx, GL_ARRAY_BUFFER);
+    AL(GRAPHICS_PROGRAM, "src", 4, GL_FLOAT, 0, sizeof(ImageRenderData));
+    AL(GRAPHICS_PROGRAM, "position", 4, GL_FLOAT, offsetof(ImageRenderData, dest_rect), sizeof(ImageRenderData));
+
     return vao_idx;
 #undef A
 #undef A1
+#undef AL
 }
 
 static inline void
@@ -560,7 +569,7 @@ init_shaders_debug(PyObject *module) {
 init_shaders(PyObject *module) {
 #endif
 #define C(x) if (PyModule_AddIntConstant(module, #x, x) != 0) { PyErr_NoMemory(); return false; }
-    C(CELL_PROGRAM); C(CELL_BACKGROUND_PROGRAM); C(CELL_SPECIAL_PROGRAM); C(CELL_FOREGROUND_PROGRAM); C(CURSOR_PROGRAM); C(BORDERS_PROGRAM);
+    C(CELL_PROGRAM); C(CELL_BACKGROUND_PROGRAM); C(CELL_SPECIAL_PROGRAM); C(CELL_FOREGROUND_PROGRAM); C(CURSOR_PROGRAM); C(BORDERS_PROGRAM); C(GRAPHICS_PROGRAM);
     C(GLSL_VERSION);
     C(GL_VERSION);
     C(GL_VENDOR);

kitty/window.py

@@ -16,9 +16,9 @@ from .constants import (
 from .fast_data_types import (
     BRACKETED_PASTE_END, BRACKETED_PASTE_START, CELL_BACKGROUND_PROGRAM,
     CELL_FOREGROUND_PROGRAM, CELL_PROGRAM, CELL_SPECIAL_PROGRAM,
-    CURSOR_PROGRAM, SCROLL_FULL, SCROLL_LINE, SCROLL_PAGE, Screen,
+    CURSOR_PROGRAM, GRAPHICS_PROGRAM, SCROLL_FULL, SCROLL_LINE, SCROLL_PAGE,
-    compile_program, create_cell_vao, glfw_post_empty_event, init_cell_program,
+    Screen, compile_program, create_cell_vao, glfw_post_empty_event,
-    init_cursor_program, remove_vao, set_window_render_data,
+    init_cell_program, init_cursor_program, remove_vao, set_window_render_data,
     update_window_title, update_window_visibility
 )
 from .rgb import to_color
@@ -62,6 +62,7 @@ def load_shader_programs():
     init_cell_program()
     compile_program(CURSOR_PROGRAM, *load_shaders('cursor'))
     init_cursor_program()
+    compile_program(GRAPHICS_PROGRAM, *load_shaders('graphics'))
 
 
 class Window: