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authorBrian Paul <brianp@vmware.com>2013-05-03 19:00:07 -0600
committerBrian Paul <brianp@vmware.com>2013-05-03 19:00:07 -0600
commit3702d2508249bb264ab502c0093dbbc10b0b02fa (patch)
treea98d030b4114aebda53cb38013aaca22ad378f44 /src
parenta232afdbfbaac156e981f55b8bdeb305026cde84 (diff)
vbo: create a few utility functions for merging primitives
To be used by following commit. Reviewed-by: Eric Anholt <eric@anholt.net> Reviewed-by: José Fonseca <jfonseca@vmware.com>
Diffstat (limited to 'src')
-rw-r--r--src/mesa/vbo/vbo.h10
-rw-r--r--src/mesa/vbo/vbo_exec.c99
2 files changed, 109 insertions, 0 deletions
diff --git a/src/mesa/vbo/vbo.h b/src/mesa/vbo/vbo.h
index 9f800d87ad5..08c67d67d43 100644
--- a/src/mesa/vbo/vbo.h
+++ b/src/mesa/vbo/vbo.h
@@ -33,6 +33,7 @@
#ifndef _VBO_H
#define _VBO_H
+#include <stdbool.h>
#include "main/glheader.h"
struct gl_client_array;
@@ -170,6 +171,15 @@ vbo_count_tessellated_primitives(GLenum mode, GLuint count,
GLuint num_instances);
void
+vbo_try_prim_conversion(struct _mesa_prim *p);
+
+bool
+vbo_can_merge_prims(const struct _mesa_prim *p0, const struct _mesa_prim *p1);
+
+void
+vbo_merge_prims(struct _mesa_prim *p0, const struct _mesa_prim *p1);
+
+void
vbo_sw_primitive_restart(struct gl_context *ctx,
const struct _mesa_prim *prim,
GLuint nr_prims,
diff --git a/src/mesa/vbo/vbo_exec.c b/src/mesa/vbo/vbo_exec.c
index 2ff1c149412..c56a14212d5 100644
--- a/src/mesa/vbo/vbo_exec.c
+++ b/src/mesa/vbo/vbo_exec.c
@@ -157,3 +157,102 @@ vbo_count_tessellated_primitives(GLenum mode, GLuint count,
}
return num_primitives * num_instances;
}
+
+
+
+/**
+ * In some degenarate cases we can improve our ability to merge
+ * consecutive primitives. For example:
+ * glBegin(GL_LINE_STRIP);
+ * glVertex(1);
+ * glVertex(1);
+ * glEnd();
+ * glBegin(GL_LINE_STRIP);
+ * glVertex(1);
+ * glVertex(1);
+ * glEnd();
+ * Can be merged as a GL_LINES prim with four vertices.
+ *
+ * This function converts 2-vertex line strips/loops into GL_LINES, etc.
+ */
+void
+vbo_try_prim_conversion(struct _mesa_prim *p)
+{
+ if (p->mode == GL_LINE_STRIP && p->count == 2) {
+ /* convert 2-vertex line strip to a separate line */
+ p->mode = GL_LINES;
+ }
+ else if ((p->mode == GL_TRIANGLE_STRIP || p->mode == GL_TRIANGLE_FAN)
+ && p->count == 3) {
+ /* convert 3-vertex tri strip or fan to a separate triangle */
+ p->mode = GL_TRIANGLES;
+ }
+
+ /* Note: we can't convert a 4-vertex quad strip to a separate quad
+ * because the vertex ordering is different. We'd have to muck
+ * around in the vertex data to make it work.
+ */
+}
+
+
+/**
+ * Helper function for determining if two subsequent glBegin/glEnd
+ * primitives can be combined. This is only possible for GL_POINTS,
+ * GL_LINES, GL_TRIANGLES and GL_QUADS.
+ * If we return true, it means that we can concatenate p1 onto p0 (and
+ * discard p1).
+ */
+bool
+vbo_can_merge_prims(const struct _mesa_prim *p0, const struct _mesa_prim *p1)
+{
+ if (!p0->begin ||
+ !p1->begin ||
+ !p0->end ||
+ !p1->end)
+ return false;
+
+ /* The prim mode must match (ex: both GL_TRIANGLES) */
+ if (p0->mode != p1->mode)
+ return false;
+
+ /* p1's vertices must come right after p0 */
+ if (p0->start + p0->count != p1->start)
+ return false;
+
+ if (p0->basevertex != p1->basevertex ||
+ p0->num_instances != p1->num_instances ||
+ p0->base_instance != p1->base_instance)
+ return false;
+
+ /* can always merge subsequent GL_POINTS primitives */
+ if (p0->mode == GL_POINTS)
+ return true;
+
+ /* independent lines with no extra vertices */
+ if (p0->mode == GL_LINES && p0->count % 2 == 0 && p1->count % 2 == 0)
+ return true;
+
+ /* independent tris */
+ if (p0->mode == GL_TRIANGLES && p0->count % 3 == 0 && p1->count % 3 == 0)
+ return true;
+
+ /* independent quads */
+ if (p0->mode == GL_QUADS && p0->count % 4 == 0 && p1->count % 4 == 0)
+ return true;
+
+ return false;
+}
+
+
+/**
+ * If we've determined that p0 and p1 can be merged, this function
+ * concatenates p1 onto p0.
+ */
+void
+vbo_merge_prims(struct _mesa_prim *p0, const struct _mesa_prim *p1)
+{
+ assert(vbo_can_merge_prims(p0, p1));
+
+ p0->count += p1->count;
+ p0->end = p1->end;
+}