1 files changed, 24 insertions, 0 deletions
diff --git a/symbols/symbols-gl.h b/symbols/symbols-gl.h
new file mode 100644
index 0000000..4c6db67
--- /dev/null
+++ b/symbols/symbols-gl.h
@@ -0,0 +1,24 @@
+#ifndef VEGA_SYMBOLS_GL_H
+#define VEGA_SYMBOLS_GL_H
+#include "symbols.h"
+#include <GLES3/gl31.h>
+
+/* Symbols drawn by the GPU (OpenGL ES 3.1): the file's point table goes up
+ * as it is, one storage buffer, and each pixel of a symbol's box sums the
+ * exact area of the curves crossing its row, as vega_coverage does. Rows
+ * are cut into bands at upload, each listing its curves, so a pixel reads
+ * only those. Needs a current context. */
+typedef struct {
+    GLuint program, points, bands, instances, array;
+    GLint viewport;
+} VegaGl;
+
+/* A symbol placed: its origin in pixels from the target's top left, and
+ * pixels per unit. */
+typedef struct { float x, y, scale; uint32_t symbol; } VegaGlyph;
+
+bool vega_gl_open(VegaGl *, const VegaSymbols *, char *error, size_t error_size);
+/* Coverage added into the red channel of the bound framebuffer. */
+void vega_gl_draw(VegaGl *, const VegaSymbols *, const VegaGlyph *, uint32_t count, int width, int height);
+void vega_gl_close(VegaGl *);
+#endif