cairo_int_status_t
_cairo_gl_composite_emit_triangle_as_tristrip (cairo_gl_context_t *ctx,
cairo_gl_composite_t *setup,
const cairo_point_t triangle[3])
{
_cairo_gl_composite_prepare_buffer (ctx, 3);
_cairo_gl_composite_emit_tristrip_vertex (ctx, &triangle[0]);
_cairo_gl_composite_emit_tristrip_vertex (ctx, &triangle[1]);
_cairo_gl_composite_emit_tristrip_vertex (ctx, &triangle[2]);
return _cairo_gl_composite_append_vertex_indices (ctx, 3);
}
cairo_int_status_t
_cairo_gl_composite_emit_triangle_as_tristrip (cairo_gl_context_t *ctx,
cairo_gl_composite_t *setup,
const cairo_point_t triangle[3])
{
_cairo_gl_composite_prepare_buffer (ctx, 3,
CAIRO_GL_PRIMITIVE_TYPE_TRISTRIPS);
_cairo_gl_composite_emit_point (ctx, &triangle[0], 0);
_cairo_gl_composite_emit_point (ctx, &triangle[1], 0);
_cairo_gl_composite_emit_point (ctx, &triangle[2], 0);
return _cairo_gl_composite_append_vertex_indices (ctx, 3);
}
cairo_int_status_t
_cairo_gl_composite_emit_point_as_single_line (cairo_gl_context_t *ctx,
const cairo_point_t point[2])
{
int num_indices = 2;
if (ctx->draw_mode != CAIRO_GL_LINES)
_cairo_gl_composite_flush (ctx);
ctx->draw_mode = CAIRO_GL_LINES;
_cairo_gl_composite_prepare_buffer (ctx, 2,
CAIRO_GL_PRIMITIVE_TYPE_TRISTRIPS);
_cairo_gl_composite_emit_point (ctx, &point[0], 0);
_cairo_gl_composite_emit_point (ctx, &point[1], 0);
return _cairo_gl_composite_append_vertex_indices (ctx, num_indices, FALSE);
}
cairo_int_status_t
_cairo_gl_composite_emit_quad_as_tristrip (cairo_gl_context_t *ctx,
cairo_gl_composite_t *setup,
const cairo_point_t quad[4])
{
_cairo_gl_composite_prepare_buffer (ctx, 4);
_cairo_gl_composite_emit_tristrip_vertex (ctx, &quad[0]);
_cairo_gl_composite_emit_tristrip_vertex (ctx, &quad[1]);
/* Cairo stores quad vertices in counter-clockwise order, but we need to
emit them from top to bottom in the triangle strip, so we need to reverse
the order of the last two vertices. */
_cairo_gl_composite_emit_tristrip_vertex (ctx, &quad[3]);
_cairo_gl_composite_emit_tristrip_vertex (ctx, &quad[2]);
return _cairo_gl_composite_append_vertex_indices (ctx, 4);
}
cairo_int_status_t
_cairo_gl_composite_emit_triangle_as_tristrip (cairo_gl_context_t *ctx,
cairo_gl_composite_t *setup,
const cairo_point_t triangle[3])
{
if (ctx->draw_mode != CAIRO_GL_VERTEX) {
_cairo_gl_composite_flush (ctx);
ctx->draw_mode = CAIRO_GL_VERTEX;
}
_cairo_gl_composite_prepare_buffer (ctx, 3,
CAIRO_GL_PRIMITIVE_TYPE_TRISTRIPS);
_cairo_gl_composite_emit_point (ctx, &triangle[0], 0);
_cairo_gl_composite_emit_point (ctx, &triangle[1], 0);
_cairo_gl_composite_emit_point (ctx, &triangle[2], 0);
return _cairo_gl_composite_append_vertex_indices (ctx, 3, TRUE);
}
cairo_int_status_t
_cairo_gl_composite_emit_quad_as_tristrip (cairo_gl_context_t *ctx,
cairo_gl_composite_t *setup,
const cairo_point_t quad[4])
{
if (ctx->draw_mode != CAIRO_GL_VERTEX) {
_cairo_gl_composite_flush (ctx);
ctx->draw_mode = CAIRO_GL_VERTEX;
}
_cairo_gl_composite_prepare_buffer (ctx, 4,
CAIRO_GL_PRIMITIVE_TYPE_TRISTRIPS);
_cairo_gl_composite_emit_point (ctx, &quad[0], 0);
_cairo_gl_composite_emit_point (ctx, &quad[1], 0);
/* Cairo stores quad vertices in counter-clockwise order, but we need to
emit them from top to bottom in the triangle strip, so we need to reverse
the order of the last two vertices. */
_cairo_gl_composite_emit_point (ctx, &quad[3], 0);
_cairo_gl_composite_emit_point (ctx, &quad[2], 0);
return _cairo_gl_composite_append_vertex_indices (ctx, 4, TRUE);
}
