4 files changed, 16 insertions, 15 deletions

diff --git a/src/mesa/main/buffers.c b/src/mesa/main/buffers.c
index 5c37f0f5376..d3640479f00 100644
--- a/src/mesa/main/buffers.c
+++ b/src/mesa/main/buffers.c
@@ -170,7 +170,7 @@ draw_buffer_enum_to_bitmask(const struct gl_context *ctx, GLenum buffer)
  * Helper routine used by glReadBuffer.
  * Given a GLenum naming a color buffer, return the index of the corresponding
  * renderbuffer (a BUFFER_* value).
- * return -1 for an invalid buffer.
+ * return BUFFER_NONE for an invalid buffer.
  */
 static gl_buffer_index
 read_buffer_enum_to_index(const struct gl_context *ctx, GLenum buffer)
@@ -719,7 +719,7 @@ _mesa_drawbuffers(struct gl_context *ctx, struct gl_framebuffer *fb,
    if (n > 0 && _mesa_bitcount(destMask[0]) > 1) {
       GLuint count = 0, destMask0 = destMask[0];
       while (destMask0) {
-         const int bufIndex = u_bit_scan(&destMask0);
+         const gl_buffer_index bufIndex = u_bit_scan(&destMask0);
          if (fb->_ColorDrawBufferIndexes[count] != bufIndex) {
             updated_drawbuffers(ctx, fb);
             fb->_ColorDrawBufferIndexes[count] = bufIndex;
@@ -733,7 +733,7 @@ _mesa_drawbuffers(struct gl_context *ctx, struct gl_framebuffer *fb,
       GLuint count = 0;
       for (buf = 0; buf < n; buf++ ) {
          if (destMask[buf]) {
-            GLint bufIndex = ffs(destMask[buf]) - 1;
+            gl_buffer_index bufIndex = ffs(destMask[buf]) - 1;
             /* only one bit should be set in the destMask[buf] field */
             assert(_mesa_bitcount(destMask[buf]) == 1);
             if (fb->_ColorDrawBufferIndexes[buf] != bufIndex) {
@@ -743,9 +743,9 @@ _mesa_drawbuffers(struct gl_context *ctx, struct gl_framebuffer *fb,
             count = buf + 1;
          }
          else {
-            if (fb->_ColorDrawBufferIndexes[buf] != -1) {
+            if (fb->_ColorDrawBufferIndexes[buf] != BUFFER_NONE) {
 	       updated_drawbuffers(ctx, fb);
-               fb->_ColorDrawBufferIndexes[buf] = -1;
+               fb->_ColorDrawBufferIndexes[buf] = BUFFER_NONE;
             }
          }
          fb->ColorDrawBuffer[buf] = buffers[buf];
@@ -753,11 +753,11 @@ _mesa_drawbuffers(struct gl_context *ctx, struct gl_framebuffer *fb,
       fb->_NumColorDrawBuffers = count;
    }
 
-   /* set remaining outputs to -1 (GL_NONE) */
+   /* set remaining outputs to BUFFER_NONE */
    for (buf = fb->_NumColorDrawBuffers; buf < ctx->Const.MaxDrawBuffers; buf++) {
-      if (fb->_ColorDrawBufferIndexes[buf] != -1) {
+      if (fb->_ColorDrawBufferIndexes[buf] != BUFFER_NONE) {
          updated_drawbuffers(ctx, fb);
-         fb->_ColorDrawBufferIndexes[buf] = -1;
+         fb->_ColorDrawBufferIndexes[buf] = BUFFER_NONE;
       }
    }
    for (buf = n; buf < ctx->Const.MaxDrawBuffers; buf++) {
diff --git a/src/mesa/main/clear.c b/src/mesa/main/clear.c
index c5e7f1346b0..be604426a0a 100644
--- a/src/mesa/main/clear.c
+++ b/src/mesa/main/clear.c
@@ -194,9 +194,9 @@ clear(struct gl_context *ctx, GLbitfield mask, bool no_error)
       if (mask & GL_COLOR_BUFFER_BIT) {
          GLuint i;
          for (i = 0; i < ctx->DrawBuffer->_NumColorDrawBuffers; i++) {
-            GLint buf = ctx->DrawBuffer->_ColorDrawBufferIndexes[i];
+            gl_buffer_index buf = ctx->DrawBuffer->_ColorDrawBufferIndexes[i];
 
-            if (buf >= 0 && color_buffer_writes_enabled(ctx, i)) {
+            if (buf != BUFFER_NONE && color_buffer_writes_enabled(ctx, i)) {
                bufferMask |= 1 << buf;
             }
          }
@@ -321,9 +321,10 @@ make_color_buffer_mask(struct gl_context *ctx, GLint drawbuffer)
       break;
    default:
       {
-         GLint buf = ctx->DrawBuffer->_ColorDrawBufferIndexes[drawbuffer];
+         gl_buffer_index buf =
+            ctx->DrawBuffer->_ColorDrawBufferIndexes[drawbuffer];
 
-         if (buf >= 0 && att[buf].Renderbuffer) {
+         if (buf != BUFFER_NONE && att[buf].Renderbuffer) {
             mask |= 1 << buf;
          }
       }
diff --git a/src/mesa/main/framebuffer.c b/src/mesa/main/framebuffer.c
index 663c4034d4a..b17d7cbc94c 100644
--- a/src/mesa/main/framebuffer.c
+++ b/src/mesa/main/framebuffer.c
@@ -563,8 +563,8 @@ update_color_draw_buffers(struct gl_context *ctx, struct gl_framebuffer *fb)
    fb->_ColorDrawBuffers[0] = NULL;
 
    for (output = 0; output < fb->_NumColorDrawBuffers; output++) {
-      GLint buf = fb->_ColorDrawBufferIndexes[output];
-      if (buf >= 0) {
+      gl_buffer_index buf = fb->_ColorDrawBufferIndexes[output];
+      if (buf != BUFFER_NONE) {
          fb->_ColorDrawBuffers[output] = fb->Attachment[buf].Renderbuffer;
       }
       else {
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index a8e2b39d40b..21e53db0902 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -3483,7 +3483,7 @@ struct gl_framebuffer
 
    /** Computed from ColorDraw/ReadBuffer above */
    GLuint _NumColorDrawBuffers;
-   GLint _ColorDrawBufferIndexes[MAX_DRAW_BUFFERS]; /**< BUFFER_x or -1 */
+   gl_buffer_index _ColorDrawBufferIndexes[MAX_DRAW_BUFFERS];
    gl_buffer_index _ColorReadBufferIndex;
    struct gl_renderbuffer *_ColorDrawBuffers[MAX_DRAW_BUFFERS];
    struct gl_renderbuffer *_ColorReadBuffer;