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-rw-r--r--symbols/symbols-gl.c331
1 files changed, 138 insertions, 193 deletions
diff --git a/symbols/symbols-gl.c b/symbols/symbols-gl.c
index 0e78efe..c1ce64e 100644
--- a/symbols/symbols-gl.c
+++ b/symbols/symbols-gl.c
@@ -1,126 +1,34 @@
#include "symbols-gl.h"
+#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
-enum { BANDS = 16 };
+enum { ATLAS_MAX = 4096 };
-/* Coordinates travel doubled, so implied points stay whole: 2x of a point
- * is its raw i16 without the flag, and an implied point's is the sum of its
- * two neighbours' coordinates. */
#define SHARED \
"#version 310 es\n" \
"precision highp float;\n" \
"precision highp int;\n"
-static const char vertex_source[] = SHARED
- "layout(location = 0) in vec4 place; /* origin x, y in pixels; pixels per unit; unused */\n"
- "layout(location = 1) in vec4 bounds; /* left, bottom, right, top in units */\n"
- "layout(location = 2) in uint bands; /* its first band */\n"
+/* Text: a quad per glyph at whole pixels, each pixel one atlas texel. */
+static const char draw_vertex[] = SHARED
+ "layout(location = 0) in ivec4 rect; /* in the atlas */\n"
+ "layout(location = 1) in ivec2 at; /* its top left on the target */\n"
"uniform vec2 target;\n"
- "out vec2 units;\n"
- "flat out float scale;\n"
- "flat out ivec2 rows; /* bottom and top in units */\n"
- "flat out uint base;\n"
+ "out vec2 texel;\n"
"void main() {\n"
- " vec2 corner = vec2(float(gl_VertexID & 1), float(gl_VertexID >> 1));\n"
- " vec2 pad = vec2(1.0 / place.z);\n"
- " units = mix(bounds.xy - pad, bounds.zw + pad, corner);\n"
- " vec2 pixel = place.xy + vec2(units.x, -units.y) * place.z;\n"
+ " vec2 corner = vec2(float(gl_VertexID & 1), float(gl_VertexID >> 1)), size = vec2(rect.zw);\n"
+ " vec2 pixel = vec2(at) + corner * size;\n"
+ " texel = vec2(rect.xy) + corner * size;\n"
" gl_Position = vec4(pixel.x / target.x * 2.0 - 1.0, 1.0 - pixel.y / target.y * 2.0, 0.0, 1.0);\n"
- " scale = place.z;\n"
- " rows = ivec2(bounds.yw);\n"
- " base = bands;\n"
"}\n";
-static const char fragment_source[] = SHARED
- "layout(std430, binding = 0) readonly buffer Points { uint points[]; };\n"
- "layout(std430, binding = 1) readonly buffer Bands { uint bands[]; };\n"
- "uniform uint listed; /* where the lists of curves start in bands */\n"
- "in vec2 units;\n"
- "flat in float scale;\n"
- "flat in ivec2 rows;\n"
- "flat in uint base;\n"
+static const char draw_fragment[] = SHARED
+ "uniform highp sampler2D atlas;\n"
+ "in vec2 texel;\n"
"out vec4 color;\n"
- "\n"
- "ivec3 point(uint i) { /* doubled x, doubled y, off */\n"
- " uint w = points[i];\n"
- " int x = int(w << 16u) >> 16, y = int(w) >> 16;\n"
- " return ivec3(x & ~1, y & ~1, x & 1);\n"
- "}\n"
- "int band(int doubled) { /* which of 16 bands a doubled y lies in */\n"
- " return clamp((doubled - 2 * rows.x) * 16 / (2 * (rows.y - rows.x) + 2), 0, 15);\n"
- "}\n"
- "int roots(float a, float b, float c, inout float ts[10], int n) {\n"
- " float r0 = -1.0, r1 = -1.0;\n"
- " if (a == 0.0) { if (b != 0.0) r0 = -c / b; }\n"
- " else {\n"
- " float d = b * b - 4.0 * a * c;\n"
- " if (d >= 0.0) {\n"
- " float q = -0.5 * (b + (b >= 0.0 ? sqrt(d) : -sqrt(d)));\n"
- " r0 = q / a;\n"
- " if (q != 0.0) r1 = c / q;\n"
- " }\n"
- " }\n"
- " if (r0 > 0.0 && r0 < 1.0) ts[n++] = r0;\n"
- " if (r1 > 0.0 && r1 < 1.0) ts[n++] = r1;\n"
- " return n;\n"
- "}\n"
- "/* As curve_area in symbols.c: the curve's share of the pixel [0, 1]^2. */\n"
- "float area(vec2 p0, vec2 p1, vec2 p2) {\n"
- " if (max(max(p0.y, p1.y), p2.y) <= 0.0 || min(min(p0.y, p1.y), p2.y) >= 1.0 || min(min(p0.x, p1.x), p2.x) >= 1.0)\n"
- " return 0.0;\n"
- " if (max(max(p0.x, p1.x), p2.x) <= 0.0) return clamp(p2.y, 0.0, 1.0) - clamp(p0.y, 0.0, 1.0);\n"
- " vec2 a = p0 - 2.0 * p1 + p2, b = p0 - p1;\n"
- " float ts[10];\n"
- " ts[0] = 0.0;\n"
- " int n = 1;\n"
- " n = roots(a.y, -2.0 * b.y, p0.y, ts, n);\n"
- " n = roots(a.y, -2.0 * b.y, p0.y - 1.0, ts, n);\n"
- " n = roots(a.x, -2.0 * b.x, p0.x, ts, n);\n"
- " n = roots(a.x, -2.0 * b.x, p0.x - 1.0, ts, n);\n"
- " ts[n++] = 1.0;\n"
- " for (int i = 1; i < n; ++i)\n"
- " for (int j = i; j > 0 && ts[j] < ts[j - 1]; --j) { float t = ts[j]; ts[j] = ts[j - 1]; ts[j - 1] = t; }\n"
- " float u0 = 1.0 - p0.x, u1 = 2.0 * b.x, u2 = -a.x, v0 = -2.0 * b.y, v1 = 2.0 * a.y;\n"
- " float k1 = u0 * v0, k2 = (u0 * v1 + u1 * v0) / 2.0, k3 = (u1 * v1 + u2 * v0) / 3.0, k4 = u2 * v1 / 4.0, sum = 0.0;\n"
- " for (int i = 0; i + 1 < n; ++i) {\n"
- " float ta = ts[i], tb = ts[i + 1], t = (ta + tb) / 2.0;\n"
- " if (tb <= ta) continue;\n"
- " float y = (a.y * t - 2.0 * b.y) * t + p0.y, x = (a.x * t - 2.0 * b.x) * t + p0.x;\n"
- " if (y <= 0.0 || y >= 1.0 || x >= 1.0) continue;\n"
- " if (x <= 0.0) sum += (a.y * tb - 2.0 * b.y) * tb - (a.y * ta - 2.0 * b.y) * ta;\n"
- " else sum += (((k4 * tb + k3) * tb + k2) * tb + k1) * tb - (((k4 * ta + k3) * ta + k2) * ta + k1) * ta;\n"
- " }\n"
- " return sum;\n"
- "}\n"
- "void main() {\n"
- " vec2 corner = units - vec2(0.5 / scale); /* the pixel's lower left, in units */\n"
- " int b0 = band(2 * int(floor(corner.y))), b1 = band(2 * int(ceil(corner.y + 1.0 / scale)));\n"
- " float sum = 0.0;\n"
- " for (int b = b0; b <= b1; ++b) {\n"
- " uint at = bands[base + 2u * uint(b)], end = at + bands[base + 2u * uint(b) + 1u];\n"
- " for (; at < end; ++at) {\n"
- " uint k = bands[listed + at];\n"
- " ivec3 p = point(k), n = point(k + 1u);\n"
- " ivec2 s, c, e;\n"
- " if (p.z == 1) {\n"
- " ivec3 q = point(k - 1u);\n"
- " s = q.z == 1 ? (q.xy + p.xy) / 2 : q.xy;\n"
- " c = p.xy;\n"
- " e = n.z == 1 ? (p.xy + n.xy) / 2 : n.xy;\n"
- " } else {\n"
- " s = p.xy;\n"
- " c = (p.xy + n.xy) / 2;\n"
- " e = n.xy;\n"
- " }\n"
- " /* a curve over several of this pixel's bands counts in the first */\n"
- " if (max(band(min(min(s.y, c.y), e.y)), b0) != b) continue;\n"
- " sum += area((vec2(s) * 0.5 - corner) * scale, (vec2(c) * 0.5 - corner) * scale, (vec2(e) * 0.5 - corner) * scale);\n"
- " }\n"
- " }\n"
- " color = vec4(min(abs(sum), 1.0), 0.0, 0.0, 1.0);\n"
- "}\n";
+ "void main() { color = vec4(texelFetch(atlas, ivec2(texel), 0).r, 0.0, 0.0, 1.0); }\n";
static GLuint compile(GLenum type, const char *source, char *error, size_t error_size) {
GLuint shader = glCreateShader(type);
@@ -136,125 +44,162 @@ static GLuint compile(GLenum type, const char *source, char *error, size_t error
return shader;
}
-/* Doubled coordinates make implied points whole; bands as the shader cuts them. */
-static int band(int doubled, int bottom, int top) {
- int b = (doubled - 2 * bottom) * BANDS / (2 * (top - bottom) + 2);
- return b < 0 ? 0 : b >= BANDS ? BANDS - 1 : b;
-}
-
-bool vega_gl_open(VegaGl *gl, const VegaSymbols *s, char *error, size_t error_size) {
+bool vega_gl_open(VegaGl *gl, char *error, size_t error_size) {
*gl = (VegaGl){0};
- GLuint vertex = compile(GL_VERTEX_SHADER, vertex_source, error, error_size);
- GLuint fragment = vertex ? compile(GL_FRAGMENT_SHADER, fragment_source, error, error_size) : 0;
- if (!fragment) return false;
- gl->program = glCreateProgram();
- glAttachShader(gl->program, vertex);
- glAttachShader(gl->program, fragment);
- glLinkProgram(gl->program);
+ GLuint vertex = compile(GL_VERTEX_SHADER, draw_vertex, error, error_size);
+ GLuint fragment = vertex ? compile(GL_FRAGMENT_SHADER, draw_fragment, error, error_size) : 0;
+ if (!fragment) {
+ if (vertex) glDeleteShader(vertex);
+ return false;
+ }
+ gl->draw = glCreateProgram();
+ glAttachShader(gl->draw, vertex);
+ glAttachShader(gl->draw, fragment);
+ glLinkProgram(gl->draw);
glDeleteShader(vertex);
glDeleteShader(fragment);
GLint ok;
- glGetProgramiv(gl->program, GL_LINK_STATUS, &ok);
+ glGetProgramiv(gl->draw, GL_LINK_STATUS, &ok);
if (!ok) {
- glGetProgramInfoLog(gl->program, (GLsizei)error_size, NULL, error);
+ glGetProgramInfoLog(gl->draw, (GLsizei)error_size, NULL, error);
+ vega_gl_close(gl);
return false;
}
- /* The point table, as the file has it. */
- glGenBuffers(1, &gl->points);
- glBindBuffer(GL_SHADER_STORAGE_BUFFER, gl->points);
- glBufferData(GL_SHADER_STORAGE_BUFFER, (GLsizeiptr)(s->points ? s->points : 1) * VEGA_POINT_BYTES,
- s->bytes + VEGA_SYMBOLS_HEADER + (size_t)s->symbols * VEGA_SYMBOL_BYTES, GL_STATIC_DRAW);
- /* Bands: per symbol, 16 (start, count) pairs into one list of curves,
- * each curve (by the point that begins it) in every band it reaches. */
- size_t table = (size_t)s->symbols * BANDS * 2, listed = 0;
- uint32_t *counts = calloc(table + 1, sizeof(*counts));
- for (int pass = 0; pass < 2; ++pass) {
- uint32_t *bands = pass ? malloc((table + listed + 1) * sizeof(*bands)) : NULL;
- size_t next = 0;
- for (uint32_t i = 0; i < s->symbols; ++i) {
- VegaSymbol symbol = vega_symbol_at(s, i);
- uint32_t *mine = pass ? bands + (size_t)i * BANDS * 2 : counts + (size_t)i * BANDS * 2;
- if (pass)
- for (int b = 0; b < BANDS; ++b) {
- mine[2 * b] = (uint32_t)next;
- next += counts[(size_t)i * BANDS * 2 + 2 * b + 1];
- mine[2 * b + 1] = 0;
- }
- VegaCurve c;
- for (uint32_t k = symbol.first; k < symbol.first + symbol.count; ++k) {
- if (!vega_symbol_curve(s, &symbol, k, &c)) continue;
- float low = c.y0 < c.y1 ? c.y0 : c.y1, high = c.y0 > c.y1 ? c.y0 : c.y1;
- low = c.y2 < low ? c.y2 : low;
- high = c.y2 > high ? c.y2 : high;
- int from = band((int)(2 * low), symbol.bottom, symbol.top), to = band((int)(2 * high), symbol.bottom, symbol.top);
- for (int b = from; b <= to; ++b) {
- if (pass) bands[table + mine[2 * b] + mine[2 * b + 1]] = k;
- ++mine[2 * b + 1];
- listed += !pass;
- }
- }
- }
- if (pass) {
- glGenBuffers(1, &gl->bands);
- glBindBuffer(GL_SHADER_STORAGE_BUFFER, gl->bands);
- glBufferData(GL_SHADER_STORAGE_BUFFER, (GLsizeiptr)((table + listed + 1) * sizeof(*bands)), bands, GL_STATIC_DRAW);
- free(bands);
- }
- }
- free(counts);
+ glUseProgram(gl->draw);
+ glUniform1i(glGetUniformLocation(gl->draw, "atlas"), 0);
+ gl->target = glGetUniformLocation(gl->draw, "target");
glGenVertexArrays(1, &gl->array);
glGenBuffers(1, &gl->instances);
glBindVertexArray(gl->array);
glBindBuffer(GL_ARRAY_BUFFER, gl->instances);
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
- glEnableVertexAttribArray(2);
- glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 36, (void *)0);
- glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 36, (void *)16);
- glVertexAttribIPointer(2, 1, GL_UNSIGNED_INT, 36, (void *)32);
+ glVertexAttribIPointer(0, 4, GL_INT, 24, (void *)0);
+ glVertexAttribIPointer(1, 2, GL_INT, 24, (void *)16);
glVertexAttribDivisor(0, 1);
glVertexAttribDivisor(1, 1);
- glVertexAttribDivisor(2, 1);
glBindVertexArray(0);
- glUseProgram(gl->program);
- glUniform1ui(glGetUniformLocation(gl->program, "listed"), (GLuint)table);
- gl->viewport = glGetUniformLocation(gl->program, "target");
if (glGetError() != GL_NO_ERROR) {
- snprintf(error, error_size, "GL error while uploading");
+ snprintf(error, error_size, "cannot set up the text program");
+ vega_gl_close(gl);
return false;
}
return true;
}
-void vega_gl_draw(VegaGl *gl, const VegaSymbols *s, const VegaGlyph *glyphs, uint32_t count, int width, int height) {
- float *instances = malloc((size_t)(count ? count : 1) * 36);
+/* The pixels a symbol reaches at scale, one more on each side. */
+static VegaPlace place_of(const VegaSymbol *symbol, float scale) {
+ if (!symbol->count) return (VegaPlace){0};
+ int left = (int)floorf(symbol->left * scale) - 1, right = (int)ceilf(symbol->right * scale) + 1;
+ int top = (int)ceilf(symbol->top * scale) + 1, bottom = (int)floorf(symbol->bottom * scale) - 1;
+ return (VegaPlace){0, 0, right - left, top - bottom, left, top};
+}
+
+bool vega_gl_atlas(VegaGl *gl, const VegaSymbols *s, float scale, const uint32_t *wanted, uint32_t count, VegaAtlas *out,
+ char *error, size_t error_size) {
+ (void)gl;
+ *out = (VegaAtlas){.scale = scale, .symbols = s->symbols};
+ if (!wanted) count = s->symbols;
+ out->places = calloc(s->symbols ? s->symbols : 1, sizeof(*out->places));
+ if (!out->places) {
+ snprintf(error, error_size, "out of memory");
+ return false;
+ }
+ /* Shelves, as wide as the square the rectangles would fill (a power of
+ * two), the next shelf starting under the tallest of the one before. */
+ uint64_t area = 0;
for (uint32_t i = 0; i < count; ++i) {
- VegaSymbol symbol = vega_symbol_at(s, glyphs[i].symbol);
- float *f = instances + (size_t)i * 9;
- f[0] = glyphs[i].x, f[1] = glyphs[i].y, f[2] = glyphs[i].scale, f[3] = 0;
- f[4] = symbol.left, f[5] = symbol.bottom, f[6] = symbol.right, f[7] = symbol.top;
- uint32_t base = glyphs[i].symbol * BANDS * 2;
- memcpy(f + 8, &base, 4);
+ uint32_t index = wanted ? wanted[i] : i;
+ if (index >= s->symbols) continue;
+ VegaSymbol symbol = vega_symbol_at(s, index);
+ VegaPlace p = place_of(&symbol, scale);
+ area += (uint64_t)p.width * (uint64_t)p.height;
}
- glUseProgram(gl->program);
- glUniform2f(gl->viewport, (float)width, (float)height);
- glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 0, gl->points);
- glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 1, gl->bands);
+ int width = 64;
+ while (width < ATLAS_MAX && (uint64_t)width * (uint64_t)width < area + area / 4) width *= 2;
+ int x = 0, y = 0, shelf = 0;
+ for (uint32_t i = 0; i < count; ++i) {
+ uint32_t index = wanted ? wanted[i] : i;
+ if (index >= s->symbols) continue;
+ VegaSymbol symbol = vega_symbol_at(s, index);
+ VegaPlace p = place_of(&symbol, scale);
+ if (!p.width) continue;
+ if (p.width > width) width = p.width;
+ if (x + p.width > width) { x = 0; y += shelf; shelf = 0; }
+ p.x = x, p.y = y;
+ x += p.width;
+ shelf = p.height > shelf ? p.height : shelf;
+ out->places[index] = p;
+ }
+ int height = y + shelf;
+ if (width > ATLAS_MAX || height > ATLAS_MAX) {
+ snprintf(error, error_size, "%u symbols at %.4f pixels a unit need %dx%d, more than one %d-pixel atlas", count,
+ (double)scale, width, height, ATLAS_MAX);
+ vega_gl_atlas_close(out);
+ return false;
+ }
+ out->width = width, out->height = height ? height : 1;
+ unsigned char *pixels = calloc((size_t)out->width * (size_t)out->height, 1);
+ if (!pixels) {
+ snprintf(error, error_size, "out of memory");
+ vega_gl_atlas_close(out);
+ return false;
+ }
+ for (uint32_t i = 0; i < s->symbols; ++i) {
+ VegaPlace p = out->places[i];
+ if (!p.width) continue;
+ VegaSymbol symbol = vega_symbol_at(s, i);
+ vega_symbol_raster(s, &symbol, scale, p.left / scale, p.top / scale, p.width, p.height,
+ pixels + (size_t)p.y * (size_t)out->width + (size_t)p.x, (size_t)out->width);
+ }
+ glGenTextures(1, &out->texture);
+ glBindTexture(GL_TEXTURE_2D, out->texture);
+ glTexStorage2D(GL_TEXTURE_2D, 1, GL_R8, out->width, out->height);
+ glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+ glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, out->width, out->height, GL_RED, GL_UNSIGNED_BYTE, pixels);
+ free(pixels);
+ if (glGetError() != GL_NO_ERROR) {
+ snprintf(error, error_size, "cannot upload the atlas");
+ vega_gl_atlas_close(out);
+ return false;
+ }
+ return true;
+}
+
+void vega_gl_draw(VegaGl *gl, const VegaAtlas *atlas, const VegaGlyph *glyphs, uint32_t count, int width, int height) {
+ int32_t *instances = malloc((size_t)(count ? count : 1) * 6 * sizeof(*instances));
+ uint32_t n = 0;
+ for (uint32_t i = 0; instances && i < count; ++i) {
+ if (glyphs[i].symbol >= atlas->symbols) continue;
+ VegaPlace p = atlas->places[glyphs[i].symbol];
+ if (!p.width) continue;
+ int32_t *q = instances + (size_t)n++ * 6;
+ q[0] = p.x, q[1] = p.y, q[2] = p.width, q[3] = p.height;
+ q[4] = glyphs[i].x + p.left, q[5] = glyphs[i].y - p.top;
+ }
+ glUseProgram(gl->draw);
+ glUniform2f(gl->target, (float)width, (float)height);
+ glActiveTexture(GL_TEXTURE0);
+ glBindTexture(GL_TEXTURE_2D, atlas->texture);
glBindVertexArray(gl->array);
glBindBuffer(GL_ARRAY_BUFFER, gl->instances);
- glBufferData(GL_ARRAY_BUFFER, (GLsizeiptr)count * 36, instances, GL_STREAM_DRAW);
+ glBufferData(GL_ARRAY_BUFFER, (GLsizeiptr)((size_t)n * 6 * sizeof(*instances)), instances, GL_STREAM_DRAW);
glEnable(GL_BLEND);
glBlendFunc(GL_ONE, GL_ONE);
- glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, (GLsizei)count);
+ if (n) glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, (GLsizei)n);
glBindVertexArray(0);
free(instances);
}
+void vega_gl_atlas_close(VegaAtlas *atlas) {
+ if (atlas->texture) glDeleteTextures(1, &atlas->texture);
+ free(atlas->places);
+ *atlas = (VegaAtlas){0};
+}
+
void vega_gl_close(VegaGl *gl) {
- glDeleteBuffers(1, &gl->points);
- glDeleteBuffers(1, &gl->bands);
- glDeleteBuffers(1, &gl->instances);
- glDeleteVertexArrays(1, &gl->array);
- glDeleteProgram(gl->program);
+ if (gl->instances) glDeleteBuffers(1, &gl->instances);
+ if (gl->array) glDeleteVertexArrays(1, &gl->array);
+ if (gl->draw) glDeleteProgram(gl->draw);
*gl = (VegaGl){0};
}
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