If binding a NULL program, disable any vertex arrays we previously en…

…abled. This is done in case the caller is switching to the fixed function pipeline and needs more control over the vertex arrays. So to minimize state changes, don't bind a NULL program between draws if you're just going to bind a new program later.
icculus · Mar 31, 2010 · 05ec90e · 05ec90e
1 parent e4c87ae
commit 05ec90e
Showing 1 changed file with 35 additions and 30 deletions.
diff --git a/mojoshader_opengl.c b/mojoshader_opengl.c
@@ -1585,6 +1585,35 @@ MOJOSHADER_glProgram *MOJOSHADER_glLinkProgram(MOJOSHADER_glShader *vshader,
 } // MOJOSHADER_glLinkProgram
 
 
+static void update_enabled_arrays(void)
+{
+    int highest_enabled = 0;
+    int i;
+
+    // Enable/disable vertex arrays to match our needs.
+    // this happens to work in both ARB1 and GLSL, but if something alien
+    //  shows up, we'll have to split these into profile*() functions.
+    for (i = 0; i <= ctx->max_attrs; i++)
+    {
+        const int want = (const int) ctx->want_attr[i];
+        const int have = (const int) ctx->have_attr[i];
+        if (want != have)
+        {
+            if (want)
+                ctx->glEnableVertexAttribArray(i);
+            else
+                ctx->glDisableVertexAttribArray(i);
+            ctx->have_attr[i] = ctx->want_attr[i];
+        } // if
+
+        if (want)
+            highest_enabled = i;
+    } // for
+
+    ctx->max_attrs = highest_enabled;  // trim unneeded iterations next time.
+} // update_enabled_arrays
+
+
 void MOJOSHADER_glBindProgram(MOJOSHADER_glProgram *program)
 {
     GLuint handle = 0;
@@ -1600,6 +1629,12 @@ void MOJOSHADER_glBindProgram(MOJOSHADER_glProgram *program)
 
     memset(ctx->want_attr, '\0', sizeof (ctx->want_attr[0]) * ctx->max_attrs);
 
+    // If no program bound, disable all arrays, in case we're switching to
+    //  fixed function pipeline. Otherwise, we try to minimize state changes
+    //  by toggling just the changed set of needed arrays in ProgramReady().
+    if (program == NULL)
+        update_enabled_arrays();
+
     ctx->profileUseProgramObject(program);
     program_unref(ctx->bound_program);
     ctx->bound_program = program;
@@ -1771,35 +1806,6 @@ void MOJOSHADER_glSetVertexAttribute(MOJOSHADER_usage usage,
 } // MOJOSHADER_glSetVertexAttribute
 
 
-static void update_enabled_arrays(void)
-{
-    int highest_enabled = 0;
-    int i;
-
-    // Enable/disable vertex arrays to match our needs.
-    // this happens to work in both ARB1 and GLSL, but if something alien
-    //  shows up, we'll have to split these into profile*() functions.
-    for (i = 0; i <= ctx->max_attrs; i++)
-    {
-        const int want = (const int) ctx->want_attr[i];
-        const int have = (const int) ctx->have_attr[i];
-        if (want != have)
-        {
-            if (want)
-                ctx->glEnableVertexAttribArray(i);
-            else
-                ctx->glDisableVertexAttribArray(i);
-            ctx->have_attr[i] = ctx->want_attr[i];
-        } // if
-
-        if (want)
-            highest_enabled = i;
-    } // for
-
-    ctx->max_attrs = highest_enabled;  // trim unneeded iterations next time.
-} // update_enabled_arrays
-
-
 void MOJOSHADER_glProgramReady(void)
 {
     MOJOSHADER_glProgram *program = ctx->bound_program;
@@ -1910,7 +1916,6 @@ void MOJOSHADER_glDestroyContext(MOJOSHADER_glContext *_ctx)
     MOJOSHADER_glContext *current_ctx = ctx;
     ctx = _ctx;
     MOJOSHADER_glBindProgram(NULL);
-    update_enabled_arrays();  // disables all vertex arrays.
     lookup_entry_points(NULL, NULL);
     Free(ctx);
     ctx = ((current_ctx == _ctx) ? NULL : current_ctx);