Fix some issues with clipping

GL/platforms/sh4.c

@@ -4,7 +4,7 @@
 #include "sh4.h"
 
 
-#define CLIP_DEBUG 1
+#define CLIP_DEBUG 0
 
 #define PVR_VERTEX_BUF_SIZE 2560 * 256
 
@@ -192,7 +192,7 @@ void SceneListSubmit(Vertex* vertices, int n) {
 
 #if CLIP_DEBUG
     fprintf(stderr, "----\n");
-    
+
     Vertex* vertex = (Vertex*) vertices;
     for(int i = 0; i < n; ++i) {
         fprintf(stderr, "IN: {%f, %f, %f, %f}, // %x (%x)\n", vertex[i].xyz[0], vertex[i].xyz[1], vertex[i].xyz[2], vertex[i].w, vertex[i].flags, &vertex[i]);
@@ -230,6 +230,27 @@ void SceneListSubmit(Vertex* vertices, int n) {
         Vertex* v1 = v0 + 1;
         Vertex* v2 = v0 + 2;
 
+        assert(!is_header(v1));
+
+        if(is_header(v2)) {
+            // OK so we've hit a new context header
+            // we need to finalize this strip and move on
+            SUBMIT_QUEUED_VERTEX(qv.flags);
+
+            _glPerspectiveDivideVertex(v0, h);
+            _glPushHeaderOrVertex(v0);
+
+            _glPerspectiveDivideVertex(v1, h);
+            _glPushHeaderOrVertex(v1);
+            i += 2;
+            continue;
+        }
+
+        assert(!is_header(v2));
+
+        // FIXME: What if v1 or v2 are headers? Should we handle that or just
+        // assume the user has done something weird and all bets are off?
+
         int visible_mask = (
             (v0->xyz[2] >= -v0->w) << 0 |
             (v1->xyz[2] >= -v1->w) << 1 |
@@ -244,9 +265,9 @@ void SceneListSubmit(Vertex* vertices, int n) {
             SUBMIT_QUEUED_VERTEX(qv.flags);
         }
 
-    #if CLIP_DEBUG
+#if CLIP_DEBUG
-            fprintf(stderr, "0x%x 0x%x 0x%x -> %d\n", v0, v1, v2, visible_mask);
+        fprintf(stderr, "0x%x 0x%x 0x%x -> %d\n", v0, v1, v2, visible_mask);
-    #endif
+#endif
 
         Vertex __attribute__((aligned(32))) scratch[4];
         Vertex* a = &scratch[0], *b = &scratch[1], *c = &scratch[2], *d = &scratch[3];
@@ -277,7 +298,7 @@ void SceneListSubmit(Vertex* vertices, int n) {
 
                 QUEUE_VERTEX(b);
             break;
-            case SECOND_VISIBLE:            
+            case SECOND_VISIBLE:
                 memcpy_vertex(c, v1);
 
                 _glClipEdge(v0, v1, a);
@@ -385,18 +406,6 @@ void SceneListSubmit(Vertex* vertices, int n) {
             default:
                 fprintf(stderr, "ERROR\n");
         }
-
-        if(v2->flags == GPU_CMD_VERTEX_EOL && visible_mask == ALL_VISIBLE) {
-            SUBMIT_QUEUED_VERTEX(qv.flags);
-
-            _glPerspectiveDivideVertex(v1, h);
-            _glPushHeaderOrVertex(v1);
-
-            _glPerspectiveDivideVertex(v2, h);
-            _glPushHeaderOrVertex(v2);
-            
-            i += 2;
-        }
     }
 
     SUBMIT_QUEUED_VERTEX(GPU_CMD_VERTEX_EOL);

samples/zclip_trianglestrip/main.c

@@ -20,7 +20,7 @@ void InitGL(int Width, int Height)	        // We call this right after our OpenG
     glEnable(GL_DEPTH_TEST);			// Enables Depth Testing
     glShadeModel(GL_SMOOTH);			// Enables Smooth Color Shading
     glEnable(GL_TEXTURE_2D);
-    glEnable(GL_CULL_FACE);
+    glDisable(GL_CULL_FACE);
 
     glMatrixMode(GL_PROJECTION);
     glLoadIdentity();				// Reset The Projection Matrix
@@ -64,30 +64,38 @@ int check_start() {
     return 0;
 }
 
+static GLfloat movement = 0.0f;
+static GLfloat rotation = 0.0f;
+
+void update_movement() {
+#ifdef __DREAMCAST__
+    maple_device_t *cont;
+    cont_state_t *state;
+
+    cont = maple_enum_type(0, MAPLE_FUNC_CONTROLLER);
+
+    if(cont) {
+        state = (cont_state_t *)maple_dev_status(cont);
+        if(state) {
+            if(state->buttons & CONT_DPAD_UP) {
+                movement += 0.5f;
+            } else if(state->buttons & CONT_DPAD_DOWN) {
+                movement -= 0.5f;
+            }
+
+            if(state->buttons & CONT_DPAD_LEFT) {
+                rotation += 0.5f;
+            } else if(state->buttons & CONT_DPAD_RIGHT) {
+                rotation -= 0.5f;
+            }
+        }
+    }
+#endif
+}
+
 /* The main drawing function. */
 void DrawGLScene()
 {
-    static GLfloat movement = 0.0f;
-    static GLfloat rotation = 0.0f;
-    static GLboolean increasing = GL_TRUE;
-
-    if(movement > 10.0) {
-        increasing = GL_FALSE;
-    } else if(movement < -10.0f) {
-        increasing = GL_TRUE;
-    }
-
-    if(increasing) {
-        movement += 0.05f;
-    } else {
-        movement -= 0.05f;
-    }
-
-    rotation += 0.1f;
-    if(rotation > 360.0f) {
-        rotation -= 360.0f;
-    }
-
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);		// Clear The Screen And The Depth Buffer
     glLoadIdentity();				// Reset The View
 
@@ -95,24 +103,58 @@ void DrawGLScene()
         glTranslatef(0.0f, -1.0f, movement);
         glRotatef(rotation, 0.0f, 1.0, 0.0f);
 
-        glBegin(GL_TRIANGLE_STRIP);
+        /* We create a horseshoe shape tri-strip here because that allows for situations where a strip
-            glColor3f(1.0f, 1.0f, 0.0f);
+           leaves and re-enters the viewport */
-            glVertex3f(-2.5f, 0.0f, 5.0f);
 
-            glColor3f(1.0f, 0.0f, 0.0f);
+        glBegin(GL_TRIANGLE_STRIP);
-            glVertex3f(2.5f, 0.0f, 5.0f);
+            // Left side
+            glColor3f(1.0f, 1.0f, 0.0f);
+            glVertex3f(-2.0f, 0.0f, 5.0f);
+
+            glColor3f(1.0f, 1.0f, 0.0f);
+            glVertex3f(-1.0f, 0.0f, 5.0f);
+
+            glColor3f(1.0f, 1.0f, 0.0f);
+            glVertex3f(-2.0f, 0.0f, 3.0f);
+
+            glColor3f(1.0f, 1.0f, 0.0f);
+            glVertex3f(-1.0f, 0.0f, 3.0f);
+
+            glColor3f(1.0f, 1.0f, 0.0f);
+            glVertex3f(-2.0f, 0.0f, 1.0f);
+
+            glColor3f(1.0f, 1.0f, 0.0f);
+            glVertex3f(-1.0f, 0.0f, 1.0f);
+
+            // Curve
+            glColor3f(0.0f, 1.0f, 0.0f);
+            glVertex3f(-1.0f, 0.0f, -1.0f);
 
             glColor3f(0.0f, 1.0f, 0.0f);
-            glVertex3f(-2.5f, 0.0f, -5.0f);
+            glVertex3f(1.0f, 0.0f, 1.0f);
 
-            glColor3f(0.0f, 0.0f, 1.0f);
+            glColor3f(0.0f, 1.0f, 0.0f);
-            glVertex3f(2.5f, 0.0f, -5.0f);
+            glVertex3f(1.0f, 0.0f, -1.0f);
 
-            glColor3f(0.0f, 1.0f, 1.0f);
+            // Right side
-            glVertex3f(-2.5f, 0.0f, -10.0f);
+            // Degenerate to reverse ordering
+            glColor3f(1.0f, 0.0f, 0.0f);
+            glVertex3f(2.0f, 0.0f, 1.0f);
 
-            glColor3f(1.0f, 0.0f, 1.0f);
+            glColor3f(0.0f, 1.0f, 0.0f);
-            glVertex3f(2.5f, 0.0f, -10.0f);
+            glVertex3f(1.0f, 0.0f, 1.0f);
+
+            glColor3f(1.0f, 0.0f, 0.0f);
+            glVertex3f(1.0f, 0.0f, 3.0f);
+
+            glColor3f(1.0f, 0.0f, 0.0f);
+            glVertex3f(2.0f, 0.0f, 3.0f);
+
+            glColor3f(1.0f, 0.0f, 0.0f);
+            glVertex3f(1.0f, 0.0f, 5.0f);
+
+            glColor3f(1.0f, 0.0f, 0.0f);
+            glVertex3f(2.0f, 0.0f, 5.0f);
         glEnd();
     glPopMatrix();
 
@@ -131,6 +173,8 @@ int main(int argc, char **argv)
         if(check_start())
             break;
 
+        update_movement();
+
         DrawGLScene();
     }