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Remove rendering via framebuffer for transparent windows with images

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There is no need for it with the current rendering pipeline. Images are
blended with premult blending.
This commit is contained in:
Kovid Goyal 2023-06-21 16:06:07 +05:30
parent 2a96b5cb25
commit 098a38a3a9
No known key found for this signature in database
GPG key ID: 06BC317B515ACE7C
11 changed files with 11 additions and 79 deletions
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9
kitty/blit_fragment.glsl
View file

@ -1,9 +0,0 @@
uniform sampler2D image;
in vec2 texcoord;
out vec4 color;
void main() {
color = texture(image, texcoord);
}

19
kitty/blit_vertex.glsl
View file

@ -1,19 +0,0 @@
#define left -1.0f
#define top 1.0f
#define right 1.0f
#define bottom -1.0f
const vec2 pos_map[] = vec2[4](
vec2(right, top),
vec2(right, bottom),
vec2(left, bottom),
vec2(left, top)
);
out vec2 texcoord;
void main() {
vec2 vertex = pos_map[gl_VertexID];
gl_Position = vec4(vertex, 0, 1);
texcoord = (vertex + 1.0) / 2.0;
}

8
kitty/cell_fragment.glsl
View file

@ -64,7 +64,8 @@ vec4 vec4_premul(vec4 rgba) {
* multiple passes drawing the background and foreground separately and blending.
*
* 2a) Opaque bg with images under text
* There are multiple passes, each pass is blended onto the previous using the opaque blend func (alpha, 1- alpha):
* There are multiple passes, each pass is blended onto the previous using the opaque blend func (alpha, 1- alpha). TRANSPARENT is not
* defined in the shaders.
* 1) Draw background for all cells
* 2) Draw the images that are supposed to be below both the background and text, if any. This happens in the graphics shader
* 3) Draw the background of cells that don't have the default background if any images were drawn in 2 above
@ -74,9 +75,8 @@ vec4 vec4_premul(vec4 rgba) {
* 7) Draw the images that are supposed to be above text again in the graphics shader
*
* 2b) Transparent bg with images
* First everything is rendered into a framebuffer, and then the framebuffer is blended onto
* the screen. The framebuffer is needed because it allows access to the background color pixels
* to blend with the image pixels. The steps are basically the same as for 2a.
* Same as (2a) except blending is done with PREMULT_BLEND and TRANSPARENT is defined in the shaders. background_opacity
* is applied to default colored background cells in step (1).
*
* In this shader exactly *one* of SIMPLE, SPECIAL, FOREGROUND or BACKGROUND will be defined, corresponding
* to the appropriate rendering pass from above.

2
kitty/child-monitor.c
View file

@ -825,7 +825,7 @@ render(monotonic_t now, bool input_read) {
bool needs_render = w->is_damaged || w->live_resize.in_progress;
if (w->viewport_size_dirty) {
w->clear_count = 0;
update_surface_size(w->viewport_width, w->viewport_height, w->offscreen_texture_id);
update_surface_size(w->viewport_width, w->viewport_height, 0);
w->viewport_size_dirty = false;
needs_render = true;
}

1
kitty/fast_data_types.pyi
View file

@ -259,7 +259,6 @@ NO_CURSOR_SHAPE: int
CURSOR_UNDERLINE: int
DECAWM: int
BGIMAGE_PROGRAM: int
BLIT_PROGRAM: int
CELL_BG_PROGRAM: int
CELL_FG_PROGRAM: int
CELL_PROGRAM: int

2
kitty/glfw.c
View file

@ -326,7 +326,7 @@ framebuffer_size_callback(GLFWwindow *w, int width, int height) {
window->live_resize.width = MAX(0, width); window->live_resize.height = MAX(0, height);
window->live_resize.num_of_resize_events++;
make_os_window_context_current(window);
update_surface_size(width, height, window->offscreen_texture_id);
update_surface_size(width, height, 0);
request_tick_callback();
} else log_error("Ignoring resize request for tiny size: %dx%d", width, height);
global_state.callback_os_window = NULL;

41
kitty/shaders.c
View file

@ -16,8 +16,8 @@
#define BLEND_ONTO_OPAQUE_WITH_OPAQUE_OUTPUT glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ZERO, GL_ONE); // blending onto opaque colors with final color having alpha 1
#define BLEND_PREMULT glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA); // blending of pre-multiplied colors
enum { CELL_PROGRAM, CELL_BG_PROGRAM, CELL_SPECIAL_PROGRAM, CELL_FG_PROGRAM, BORDERS_PROGRAM, GRAPHICS_PROGRAM, GRAPHICS_PREMULT_PROGRAM, GRAPHICS_ALPHA_MASK_PROGRAM, BLIT_PROGRAM, BGIMAGE_PROGRAM, TINT_PROGRAM, NUM_PROGRAMS };
enum { SPRITE_MAP_UNIT, GRAPHICS_UNIT, BLIT_UNIT, BGIMAGE_UNIT };
enum { CELL_PROGRAM, CELL_BG_PROGRAM, CELL_SPECIAL_PROGRAM, CELL_FG_PROGRAM, BORDERS_PROGRAM, GRAPHICS_PROGRAM, GRAPHICS_PREMULT_PROGRAM, GRAPHICS_ALPHA_MASK_PROGRAM, BGIMAGE_PROGRAM, TINT_PROGRAM, NUM_PROGRAMS };
enum { SPRITE_MAP_UNIT, GRAPHICS_UNIT, BGIMAGE_UNIT };
// Sprites {{{
typedef struct {
@ -818,26 +818,12 @@ draw_cells_interleaved_premult(ssize_t vao_idx, ssize_t gvao_idx, Screen *screen
draw_tint(true, screen, crd);
glDisable(GL_BLEND);
}
if (!os_window->offscreen_texture_id) {
glGenFramebuffers(1, &os_window->offscreen_framebuffer);
glGenTextures(1, &os_window->offscreen_texture_id);
glBindTexture(GL_TEXTURE_2D, os_window->offscreen_texture_id);
glTexImage2D(GL_TEXTURE_2D, 0, GL_SRGB_ALPHA, os_window->viewport_width, os_window->viewport_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
}
glBindTexture(GL_TEXTURE_2D, 0);
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, os_window->offscreen_framebuffer);
glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, os_window->offscreen_texture_id, 0);
/* if (glCheckFramebufferStatus(GL_DRAW_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) fatal("Offscreen framebuffer not complete"); */
bind_program(CELL_BG_PROGRAM);
if (!has_bgimage(os_window)) {
// draw background for all cells
glUniform1ui(cell_program_layouts[CELL_BG_PROGRAM].draw_bg_bitfield_location, 3);
glDrawArraysInstanced(GL_TRIANGLE_FAN, 0, 4, screen->lines * screen->columns);
} else blank_canvas(0, 0);
}
glEnable(GL_BLEND);
BLEND_PREMULT;
@ -870,22 +856,7 @@ draw_cells_interleaved_premult(ssize_t vao_idx, ssize_t gvao_idx, Screen *screen
if (screen->grman->num_of_positive_refs) draw_graphics(GRAPHICS_PREMULT_PROGRAM, vao_idx, gvao_idx, screen->grman->render_data, screen->grman->num_of_negative_refs + screen->grman->num_of_below_refs, screen->grman->num_of_positive_refs);
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
if (!has_bgimage(os_window)) glDisable(GL_BLEND);
glEnable(GL_SCISSOR_TEST);
// Now render the framebuffer to the screen
bind_program(BLIT_PROGRAM);
static bool blit_constants_set = false;
if (!blit_constants_set) {
glUniform1i(glGetUniformLocation(program_id(BLIT_PROGRAM), "image"), BLIT_UNIT);
blit_constants_set = true;
}
glActiveTexture(GL_TEXTURE0 + BLIT_UNIT);
glBindTexture(GL_TEXTURE_2D, os_window->offscreen_texture_id);
glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
glDisable(GL_SCISSOR_TEST);
glDisable(GL_BLEND);
}
void
@ -964,10 +935,6 @@ draw_cells(ssize_t vao_idx, ssize_t gvao_idx, const ScreenRenderData *srd, OSWin
// The scissor limits below are calculated to ensure that they do not
// overlap with the pixels outside the draw area. We can't use the actual pixel window dimensions
// because of the mapping of opengl's float based co-ord system to pixels.
// for a test case (scissor is used to blit framebuffer in draw_cells_interleaved_premult) run:
// kitty -o background=cyan -o background_opacity=0.7 -o cursor_blink_interval=0 -o window_margin_width=40 -o remember_initial_window_size=n -o initial_window_width=401 kitty +kitten icat --hold logo/kitty.png
// Repeat incrementing window width by 1px each time over cursor_width number of pixels and see if any lines
// appear at the borders of the content area
unsigned scissor_base_width = os_window->live_resize.in_progress ? os_window->live_resize.width : (unsigned)os_window->viewport_width;
unsigned scissor_base_height = os_window->live_resize.in_progress ? os_window->live_resize.height: (unsigned)os_window->viewport_height;
#define SCALE(w, x) ((GLfloat)(scissor_base_##w) * (GLfloat)(x))
@ -1201,7 +1168,7 @@ static PyMethodDef module_methods[] = {
bool
init_shaders(PyObject *module) {
#define C(x) if (PyModule_AddIntConstant(module, #x, x) != 0) { PyErr_NoMemory(); return false; }
C(CELL_PROGRAM); C(CELL_BG_PROGRAM); C(CELL_SPECIAL_PROGRAM); C(CELL_FG_PROGRAM); C(BORDERS_PROGRAM); C(GRAPHICS_PROGRAM); C(GRAPHICS_PREMULT_PROGRAM); C(GRAPHICS_ALPHA_MASK_PROGRAM); C(BLIT_PROGRAM); C(BGIMAGE_PROGRAM); C(TINT_PROGRAM);
C(CELL_PROGRAM); C(CELL_BG_PROGRAM); C(CELL_SPECIAL_PROGRAM); C(CELL_FG_PROGRAM); C(BORDERS_PROGRAM); C(GRAPHICS_PROGRAM); C(GRAPHICS_PREMULT_PROGRAM); C(GRAPHICS_ALPHA_MASK_PROGRAM); C(BGIMAGE_PROGRAM); C(TINT_PROGRAM);
C(GLSL_VERSION);
C(GL_VERSION);
C(GL_VENDOR);

2
kitty/shaders.py
View file

@ -9,7 +9,6 @@
from .constants import read_kitty_resource
from .fast_data_types import (
BGIMAGE_PROGRAM,
BLIT_PROGRAM,
CELL_BG_PROGRAM,
CELL_FG_PROGRAM,
CELL_PROGRAM,
@ -149,7 +148,6 @@ def __call__(self, semi_transparent: bool = False, allow_recompile: bool = False
opts = get_options()
self.text_old_gamma = opts.text_composition_strategy == 'legacy'
self.text_fg_override_threshold = max(0, min(opts.text_fg_override_threshold, 100)) * 0.01
program_for('blit').compile(BLIT_PROGRAM, allow_recompile)
cell = program_for('cell')
if self.cell_program_replacer is null_replacer:
self.cell_program_replacer = MultiReplacer(

2
kitty/state.c
View file

@ -477,8 +477,6 @@ destroy_os_window_item(OSWindow *w) {
remove_tab_inner(w, tab->id);
}
Py_CLEAR(w->window_title); Py_CLEAR(w->tab_bar_render_data.screen);
if (w->offscreen_texture_id) free_texture(&w->offscreen_texture_id);
if (w->offscreen_framebuffer) free_framebuffer(&w->offscreen_framebuffer);
remove_vao(w->tab_bar_render_data.vao_idx);
remove_vao(w->gvao_idx);
free(w->tabs); w->tabs = NULL;

2
kitty/state.h
View file

@ -189,7 +189,6 @@ typedef struct {
typedef struct {
void *handle;
id_type id;
uint32_t offscreen_framebuffer;
struct {
int x, y, w, h;
bool is_set, was_maximized;
@ -216,7 +215,6 @@ typedef struct {
monotonic_t viewport_resized_at;
LiveResizeInfo live_resize;
bool has_pending_resizes, is_semi_transparent, shown_once, is_damaged;
uint32_t offscreen_texture_id;
unsigned int clear_count;
color_type last_titlebar_color;
float background_opacity;

2
kitty_tests/check_build.py
View file

@ -32,7 +32,7 @@ def test_loading_extensions(self) -> None:
def test_loading_shaders(self) -> None:
from kitty.shaders import Program
for name in 'cell border bgimage tint blit graphics'.split():
for name in 'cell border bgimage tint graphics'.split():
Program(name)
def test_glfw_modules(self) -> None: