fix stbi_shiftsigned to be shifting a value that's unsigned

stb_image.h

@@ -4960,7 +4960,7 @@ static int stbi__bitcount(unsigned int a)
    return a & 0xff;
 }
 
-static int stbi__shiftsigned(int v, int shift, int bits)
+static unsigned int stbi__shiftsigned(unsigned int v, int shift, int bits)
 {
    int result;
    int z=0;
@@ -4969,6 +4969,7 @@ static int stbi__shiftsigned(int v, int shift, int bits)
    else v >>= shift;
    result = v;
 
+   // replicate the high bits to the low bits
    z = bits;
    while (z < 8) {
       result += v >> z;
@@ -5185,7 +5186,7 @@ static void *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int req
             int bpp = info.bpp;
             for (i=0; i < (int) s->img_x; ++i) {
                stbi__uint32 v = (bpp == 16 ? (stbi__uint32) stbi__get16le(s) : stbi__get32le(s));
-               int a;
+               unsigned int a;
                out[z++] = STBI__BYTECAST(stbi__shiftsigned(v & mr, rshift, rcount));
                out[z++] = STBI__BYTECAST(stbi__shiftsigned(v & mg, gshift, gcount));
                out[z++] = STBI__BYTECAST(stbi__shiftsigned(v & mb, bshift, bcount));

tests/caveview/cave_mesher.c

@@ -37,7 +37,8 @@ extern void ods(char *fmt, ...);
 #define FAST_CHUNK
 #define IN_PLACE
 
-#define SKIP_TERRAIN   48 // use to avoid building underground stuff
+#define SKIP_TERRAIN   0
+//#define SKIP_TERRAIN   48 // use to avoid building underground stuff
                           // allows you to see what perf would be like if underground was efficiently culled,
                           // or if you were making a game without underground
 
@@ -131,7 +132,8 @@ unsigned char minecraft_info[256][7] =
    { C_solid, 35,35,35,35,4,4, },
 
    // 48
-   { C_solid, 36,36,36,36,36,36 },
+   //{ C_solid, 36,36,36,36,36,36 },
+   { C_force, 36,36,36,36,36,36 },
    { C_solid, 37,37,37,37,37,37 },
    { C_cross, 80,80,80,80,80,80 }, // torch
    { C_empty }, // fire
@@ -142,6 +144,7 @@ unsigned char minecraft_info[256][7] =
 
    // 56
    { C_solid, 50,50,50,50,50,50 },
+   //{ C_force, 50,50,50,50,50,50 },
    { C_solid, 26,26,26,26,26,26 },
    { C_solid, 60,59,59,59,43,43 },
    { C_cross, 95,95,95,95 },
@@ -831,6 +834,8 @@ void mesh_init(void)
       minecraft_color_for_blocktype[161][i] = 37 | 64; // green
       minecraft_color_for_blocktype[10][i] = 63; // emissive lava
       minecraft_color_for_blocktype[11][i] = 63; // emissive
+      //minecraft_color_for_blocktype[56][i] = 63; // emissive diamond
+      minecraft_color_for_blocktype[48][i] = 63; // emissive dungeon
    }
 
    #ifdef VHEIGHT_TEST