Add todos

small3dlib.h

@@ -185,16 +185,29 @@ typedef uint16_t S3L_Index;
                                              S3L_Z_BUFFER_*. */
 #endif
 
-#if S3L_Z_BUFFER == S3L_Z_BUFFER_FULL
+#define S3L_SORT_NONE 0          /**< Don't sort triangles. This is fastest. */
-  #define S3L_COMPUTE_DEPTH 1
+#define S3L_SORT_BACK_TO_FRONT 1 /**< Sort triangles from back to front. This
-  #define S3L_MAX_DEPTH 2147483647
+                                      can in most cases solve visibility
-  S3L_Unit S3L_zBuffer[S3L_RESOLUTION_X * S3L_RESOLUTION_Y];
+                                      without requiring almost any extra
-  #define S3L_zBufferFormat(depth) (depth)
+                                      memory compared to z-buffer. */
-#elif S3L_Z_BUFFER == S3L_Z_BUFFER_BYTE
+#define S3L_SORT_FRONT_TO_BACK 2 /**< Sort triangles front to back AND use
-  #define S3L_COMPUTE_DEPTH 1
+                                      a 1bit stencil buffer to not draw over
-  #define S3L_MAX_DEPTH 255
+                                      already drawn triangles. This prevents
-  uint8_t S3L_zBuffer[S3L_RESOLUTION_X * S3L_RESOLUTION_Y];
+                                      overwriting already computed pixels, but
-  #define S3L_zBufferFormat(depth) (((depth) >> 5) & 0x000000FF)
+                                      requires a little but extra memory (the
+                                      stencil buffer). */
+#ifndef S3L_SORT
+#define S3L_SORT S3L_SORT_NONE /**< Defines how to sort triangles before
+                                    drawing a frame. This can be used to solve
+                                    visibility in case z-buffer is not used, to
+                                    prevent overwrting already rasterized
+                                    pixels, implement transparency etc. Note
+                                    that for simplicity and performance a
+                                    relatively simple sorting is used which
+                                    doesn't work completely correctly, so
+                                    mistakes can occur (even the best sorting
+                                    wouldn't be able to solve e.g. intersecting
+                                    triangles). */
 #endif
 
 #ifndef S3L_NEAR
@@ -509,6 +522,18 @@ static inline void S3L_rotate2DPoint(S3L_Unit *x, S3L_Unit *y, S3L_Unit angle);
 //=============================================================================
 // privates
 
+#if S3L_Z_BUFFER == S3L_Z_BUFFER_FULL
+  #define S3L_COMPUTE_DEPTH 1
+  #define S3L_MAX_DEPTH 2147483647
+  S3L_Unit S3L_zBuffer[S3L_RESOLUTION_X * S3L_RESOLUTION_Y];
+  #define S3L_zBufferFormat(depth) (depth)
+#elif S3L_Z_BUFFER == S3L_Z_BUFFER_BYTE
+  #define S3L_COMPUTE_DEPTH 1
+  #define S3L_MAX_DEPTH 255
+  uint8_t S3L_zBuffer[S3L_RESOLUTION_X * S3L_RESOLUTION_Y];
+  #define S3L_zBufferFormat(depth) (((depth) >> 5) & 0x000000FF)
+#endif
+
 #define S3L_COMPUTE_LERP_DEPTH\
   (S3L_COMPUTE_DEPTH && (S3L_PERSPECTIVE_CORRECTION != 1))
 

testSDL.c

@@ -7,7 +7,7 @@
 #include <stdio.h>
 #include <math.h>
 
-#define S3L_Z_BUFFER S3L_Z_BUFFER_FULL
+#define S3L_Z_BUFFER 0
 
 #define S3L_PIXEL_FUNCTION drawPixel
 
@@ -15,7 +15,7 @@
 #define S3L_RESOLUTION_Y 480
 
 #define S3L_COMPUTE_DEPTH 1
-#define S3L_PERSPECTIVE_CORRECTION 1
+#define S3L_PERSPECTIVE_CORRECTION 0
 
 #include "small3dlib.h"
 

todo.txt

@@ -1,11 +1,14 @@
 features:
 
-- scene and model rendering strategies:
+- scene and model rendering strategies, that can be optionally selected and 
-  - random (no visibility checks)
+  will configure other constants (e.g. a "low memory sort strategy" will turn
-  - sorted:
+  z-buffer off and turn back-to-front sorting on).
+
+- triangle sorting:
   - back-to-front (slower, better memory efficiency)
   - front-to-back (faster, but needs 1bit stencil buffer)
-  - Z-buffer:
+
+- Z-buffer:
   - full                                  DONE
   - reduced (resolution and precision)    DONE
   - more reduced (4-bit)