#version 450
const uint N_GLYPHS = 384;const uint THUMB_WIDTH = 16;
struct Cell { uint glyph; uint modifier; uint foreground; uint background;};
layout (binding = 0) buffer readonly restrict GRID { Cell grid[];};
layout (binding = 1) buffer readonly restrict GLYPH_BUFFER { uint glyph_buffer[];};
layout (push_constant) uniform PARAMS { uvec2 view_origin; uvec2 view_size; uvec2 cell_size; uvec2 thumb_pos; ivec2 cursor; uint thumb_color; uint cursor_color; uint columns; uint grid_cell_offset; // offset in cells (16 or so bytes) uint glyphset_byte_offset; // offset in bytes uint glyph_overlap_w; uint glyph_full_w;} params;
layout (location = 0) out vec4 outColor;
float get_glyph_value(uint slot, uint pos, uint full_cell_w) { uint idx = params.glyphset_byte_offset + (slot * full_cell_w * params.cell_size.y) + pos;
uint shift = (idx & 3) * 8; uint value = (glyph_buffer[idx / 4] >> shift) & 0xff;
return float(value) / 255.0;}
vec3 get_color(uint c) { return vec3((c >> 24) & 0xff, (c >> 16) & 0xff, (c >> 8) & 0xff) / 255.0;}
void main() { uvec2 view_pos = uvec2(gl_FragCoord.xy) - params.view_origin;
if (view_pos.x >= params.view_size.x - THUMB_WIDTH && view_pos.y >= params.thumb_pos.x && view_pos.y < params.thumb_pos.x + params.thumb_pos.y ) { outColor = vec4(get_color(params.thumb_color), 1.0); return; }
uint cell_w = params.cell_size.x; uint full_cell_w = params.glyph_full_w;
uint outer_row = view_pos.y / params.cell_size.y; uint inner_row = view_pos.y % params.cell_size.y;
uint outer_col = view_pos.x / cell_w; uint inner_col = view_pos.x % cell_w;
uint bar_h = 1 + (params.cell_size.y / 20); uint bar_mid = (params.cell_size.y - bar_h) / 2;
uint row_start_cell = params.grid_cell_offset + outer_row * params.columns;
uint cell_idx = row_start_cell + outer_col; uint modifier = grid[cell_idx].modifier; uint top = modifier * bar_mid;
vec3 back = get_color(grid[cell_idx].background); vec3 fore_cur = get_color(grid[cell_idx].foreground); vec3 fore = fore_cur; float lum = 0.0;
if (outer_row == params.cursor.y && outer_col == params.cursor.x && inner_col < params.glyph_overlap_w) { lum = 1.0; fore = get_color(params.cursor_color); } else if (modifier > 0 && inner_row >= top && inner_row < top + bar_h) { lum = 1.0; } else { uint glyph_pixel_offset = inner_row * full_cell_w; uint next_threshold = full_cell_w - params.glyph_overlap_w;
uint pos = glyph_pixel_offset + inner_col + params.glyph_overlap_w; float value_cur = get_glyph_value(grid[cell_idx].glyph, pos, full_cell_w); lum = value_cur;
if (outer_col > 0 && inner_col <= params.glyph_overlap_w) { uint prev_pos = glyph_pixel_offset + cell_w + params.glyph_overlap_w + inner_col; uint prev_idx = cell_idx - 1; float value_prev = get_glyph_value(grid[prev_idx].glyph, prev_pos, full_cell_w);
float value = value_cur + value_prev; if (value > 0.0) { lum = clamp(value, 0.0, 1.0); fore = mix(fore_cur, get_color(grid[prev_idx].foreground), value_prev / value); } } }
outColor = vec4(mix(back, fore, lum), 1.0);}