Allow toggling z clipping

GL/clip.c

@@ -11,6 +11,16 @@
 #include "../containers/aligned_vector.h"
 
 
+static unsigned char ZCLIP_ENABLED = 1;
+
+unsigned char isClippingEnabled() {
+    return ZCLIP_ENABLED;
+}
+
+void enableClipping(unsigned char v) {
+    ZCLIP_ENABLED = v;
+}
+
 void clipLineToNearZ(const ClipVertex* v1, const ClipVertex* v2, ClipVertex* vout, float* t) {
     const float NEAR_PLANE = 0.2; // FIXME: this needs to be read from the projection matrix.. somehow
 

GL/draw.c

@@ -479,7 +479,11 @@ static void submitVertices(GLenum mode, GLsizei first, GLsizei count, GLenum typ
     generate(buffer, mode, first, count, (GLubyte*) indices, type, vptr, vstride, cptr, cstride, uvptr, uvstride, nptr, nstride);
     light(buffer);
     transform(buffer);
+
+    if(isClippingEnabled()) {
         clip(buffer);
+    }
+
     divide(buffer);
     push(buffer, activePolyList());
 }

GL/private.h

@@ -91,6 +91,9 @@ GLboolean isLightingEnabled();
 GLboolean isLightEnabled(GLubyte light);
 void calculateLightingContribution(const GLint light, const GLfloat* pos, const GLfloat* normal, GLfloat* colour);
 
+unsigned char isClippingEnabled();
+void enableClipping(unsigned char v);
+
 void _glKosThrowError(GLenum error, const char *function);
 void _glKosPrintError();
 GLubyte _glKosHasError();

GL/state.c

@@ -6,6 +6,8 @@
 #include <dc/video.h>
 
 #include "../include/gl.h"
+#include "../include/glkos.h"
+
 #include "private.h"
 
 static pvr_poly_cxt_t GL_CONTEXT;
@@ -218,6 +220,9 @@ GLAPI void APIENTRY glEnable(GLenum cap) {
         case GL_LIGHT7:
             LIGHT_ENABLED[cap & 0xF] = GL_TRUE;
         break;
+        case GL_NEARZ_CLIPPING_KOS:
+            enableClipping(GL_TRUE);
+        break;
     default:
         break;
     }
@@ -259,6 +264,9 @@ GLAPI void APIENTRY glDisable(GLenum cap) {
         case GL_LIGHT7:
             LIGHT_ENABLED[cap & 0xF] = GL_FALSE;
         break;
+        case GL_NEARZ_CLIPPING_KOS:
+            enableClipping(GL_FALSE);
+        break;
     default:
         break;
     }

include/gl.h

@@ -329,9 +329,6 @@ __BEGIN_DECLS
 #define GL_VERSION                        0x1F02
 #define GL_EXTENSIONS                     0x1F03
 
-/* GL KOS near Z-CLIPPING */
-#define GL_KOS_NEARZ_CLIPPING       0x0020      /* capability bit */
-
 /* GL KOS Texture Matrix Enable Bit */
 #define GL_KOS_TEXTURE_MATRIX       0x002F
 

include/glkos.h

@@ -5,6 +5,9 @@
 
 __BEGIN_DECLS
 
+
+#define GL_NEARZ_CLIPPING_KOS                 0xEEFA
+
 #define GL_COLOR_ATTACHMENT0_EXT              0x8CE0
 #define GL_COLOR_ATTACHMENT1_EXT              0x8CE1
 #define GL_COLOR_ATTACHMENT2_EXT              0x8CE2

samples/terrain/main.c

@@ -5,7 +5,7 @@
 #include "glu.h"
 #include "glkos.h"
 
-#define TERRAIN_SIZE 250
+#define TERRAIN_SIZE 100
 #define TERRAIN_SCALE 1.0f
 #define TERRAIN_HEIGHT_SCALE 1.0f