Add transparent plant

programs/modelViewer.c

@@ -31,6 +31,9 @@
 #include "chestTexture.h"
 #include "chestModel.h"
 
+#include "plantTexture.h"
+#include "plantModel.h"
+
 #include "cat1Model.h"
 #include "cat2Model.h"
 #include "catTexture.h"
@@ -40,7 +43,8 @@
 
 S3L_Unit houseNormals[HOUSE_VERTEX_COUNT * 3];
 S3L_Unit chestNormals[CHEST_VERTEX_COUNT * 3];
-S3L_Unit catNormals[CHEST_VERTEX_COUNT * 3];
+S3L_Unit catNormals[CAT1_VERTEX_COUNT * 3];
+S3L_Unit plantNormals[PLANT_VERTEX_COUNT * 3];
 
 S3L_Unit catVertices[CAT1_VERTEX_COUNT * 3];
 const S3L_Index *catTriangleIndices = cat1TriangleIndices;
@@ -127,6 +131,7 @@ S3L_Vec4 toLight;
 int8_t light = 1;
 int8_t fog = 0;
 int8_t noise = 0;
+int8_t transparency = 0;
 int8_t mode = 0;
 S3L_Vec4 n0, n1, n2, nt;
 
@@ -232,6 +237,8 @@ void drawPixel(S3L_PixelInfo *p)
 
   uint8_t r,g,b;
 
+  int8_t transparent = 0;
+
   switch (mode)
   {
     case 0: // textured mode
@@ -246,6 +253,9 @@ void drawPixel(S3L_PixelInfo *p)
 
       sampleTexture(uv[0] / 4,uv[1] / 4,&r,&g,&b);
 
+      if (transparency && r == 255 && g == 0 && b == 0)
+        transparent = 1;
+
       break;
     }
 
@@ -321,6 +331,12 @@ void drawPixel(S3L_PixelInfo *p)
     b = S3L_clamp(((int16_t) b) + f,0,255);
   }
 
+  if (transparency && transparent)
+  {
+    S3L_zBufferWrite(p->x,p->y,p->previousZ);
+    return;
+  }
+
   if (noise)
     setPixel(p->x + rand() % 8,p->y + rand() % 8,r,g,b); 
   else
@@ -355,6 +371,7 @@ void setModel(uint8_t index)
     modelCase(0,house)
     modelCase(1,chest)
     modelCase(2,cat)
+    modelCase(3,plant)
 
     default:
       break;
@@ -364,6 +381,17 @@ void setModel(uint8_t index)
 
   S3L_initTransoform3D(&(scene.models[0].transform));
   S3L_initDrawConfig(&(scene.models[0].config));
+
+  if (index == 3)
+  {
+    scene.models[0].config.backfaceCulling = 0;
+    transparency = 1;
+  }
+  else
+  {
+    scene.models[0].config.backfaceCulling = 2;
+    transparency = 0;
+  }
 }
 
 int16_t fps = 0;
@@ -394,7 +422,7 @@ int main()
   scene.models = &model;
 
   int8_t modelIndex = 0;
-  int8_t modelsTotal = 3;
+  int8_t modelsTotal = 4;
   setModel(0);
 
   int running = 1;

programs/plantModel.h

@@ -0,0 +1,52 @@
+#ifndef PLANT_MODEL_H
+#define PLANT_MODEL_H
+
+#define PLANT_VERTEX_COUNT 8
+const S3L_Unit plantVertices[PLANT_VERTEX_COUNT * 3] = {
+  -1604, -1546,     0,        // 0
+   1604, -1546,     0,        // 3
+  -1604,  2293,     0,        // 6
+   1604,  2293,     0,        // 9
+      0, -1546, -1604,        // 12
+      0, -1546,  1604,        // 15
+      0,  2293, -1604,        // 18
+      0,  2293,  1604         // 21
+}; // plantVertices
+
+#define PLANT_TRIANGLE_COUNT 4
+const S3L_Index plantTriangleIndices[PLANT_TRIANGLE_COUNT * 3] = {
+      1,     2,     0,        // 0
+      5,     6,     4,        // 3
+      1,     3,     2,        // 6
+      5,     7,     6         // 9
+}; // plantTriangleIndices
+
+#define PLANT_UV_COUNT 8
+const S3L_Unit plantUVs[PLANT_UV_COUNT * 2] = {
+    512,   512,         // 0
+      0,     0,         // 2
+      0,   512,         // 4
+    512,   512,         // 6
+      0,     0,         // 8
+      0,   512,         // 10
+    512,     0,         // 12
+    512,     0          // 14
+}; // plantUVs
+
+#define PLANT_UV_INDEX_COUNT 4
+const S3L_Index plantUVIndices[PLANT_UV_INDEX_COUNT * 3] = {
+      0,     1,     2,        // 0
+      3,     4,     5,        // 3
+      0,     6,     1,        // 6
+      3,     7,     4         // 9
+}; // plantUVIndices
+
+S3L_Model3D plantModel = 
+{
+  .vertices = plantVertices,
+  .vertexCount = PLANT_VERTEX_COUNT,
+  .triangles = plantTriangleIndices,
+  .triangleCount = PLANT_TRIANGLE_COUNT
+};
+
+#endif // guard

small3dlib.h

@@ -434,10 +434,11 @@ typedef struct
   S3L_Index triangleIndex;  ///< Triangle index.
   S3L_Index modelIndex;
   S3L_Unit depth;         ///< Depth (only if depth is turned on).
-  S3L_Unit previousDepth; /**< Depth that was in the z-buffer on the pixels
-                               position before this pixel was rasterized. This
-                               can be used to set the value back, e.g. for
-                               transparency. */
+  S3L_Unit previousZ;     /**< Z-buffer value (not necessarily world depth in
+                               S3L_Units!) that was in the z-buffer on the
+                               pixels position before this pixel was
+                               rasterized. This can be used to set the value
+                               back, e.g. for transparency. */
   S3L_ScreenCoord triangleSize[2]; /**< Rasterized triangle width and height,
                               can be used e.g. for MIP mapping. */
 } S3L_PixelInfo;         /**< Used to pass the info about a rasterized pixel
@@ -652,10 +653,6 @@ S3L_Unit S3L_zBufferRead(S3L_ScreenCoord x, S3L_ScreenCoord y)
 void S3L_zBufferWrite(S3L_ScreenCoord x, S3L_ScreenCoord y, S3L_Unit value)
 {
 #if S3L_Z_BUFFER
-  uint32_t index = y * S3L_RESOLUTION_X + x;
-
-  value = S3L_zBufferFormat(value);
-
   S3L_zBuffer[y * S3L_RESOLUTION_X + x] = value;
 #endif
 }
@@ -663,7 +660,8 @@ void S3L_zBufferWrite(S3L_ScreenCoord x, S3L_ScreenCoord y, S3L_Unit value)
 #if S3L_STENCIL_BUFFER
   #define S3L_STENCIL_BUFFER_SIZE\
     ((S3L_RESOLUTION_X * S3L_RESOLUTION_Y - 1) / 8 + 1)
-  uint8_t S3L_stencilBuffer[S3L_STENCIL_BUFFER_SIZE];
+
+uint8_t S3L_stencilBuffer[S3L_STENCIL_BUFFER_SIZE];
 
 static inline int8_t S3L_stencilTest(
   S3L_ScreenCoord x,
@@ -1372,7 +1370,7 @@ void S3L_initPixelInfo(S3L_PixelInfo *p) // TODO: maybe non-pointer for p
   p->barycentric[2] = 0;
   p->triangleIndex = 0;
   p->depth = 0;
-  p->previousDepth = 0;
+  p->previousZ = 0;
 }
 
 void S3L_initDrawConfig(S3L_DrawConfig *config)
@@ -1897,10 +1895,10 @@ void S3L_drawTriangle(
 #endif
 
 #if S3L_Z_BUFFER
+        p.previousZ = S3L_zBuffer[p.y * S3L_RESOLUTION_X + p.x];
+
         if (!S3L_zTest(p.x,p.y,p.depth))
-          testsPassed = 0;
-        
-        p.previousDepth = S3L_zBuffer[p.y * S3L_RESOLUTION_X + p.x];
+          testsPassed = 0;        
 #endif
 
         if (testsPassed)