transparency

3 files changed, 47 insertions, 25 deletions

diff --git a/src/main.c b/src/main.c
index f44e527..2d8f351 100644
--- a/src/main.c
+++ b/src/main.c
@@ -33,16 +33,17 @@ main(void)
 		y -= TZR_IsKeyDown(SDL_SCANCODE_W);
 		y += TZR_IsKeyDown(SDL_SCANCODE_S);
 
-		pxClipReset();
 		pxCls(1);
+
+		pxPalt();
+		pxSpr(&spr, x, y);
+
+		pxPalt(0);
+		pxSpr(&spr, x, y + 8);
+
 		pxPset(0, 0, 10);
 		pxPset(1, 0, 10);
 		pxPset(0, 1, pxPget(0, 0));
-		pxClip(25, 12, 32, 69);
-		pxCls(2);
-		pxClipReset();
-		pxSpr(&spr, x, y);
-		pxSpr(&spr, 24, 8, .iy=1, .h=2);
 
 		TZR_DrawBegin();
 		pxRender();
diff --git a/src/px.c b/src/px.c
index 7eed959..629a7de 100644
--- a/src/px.c
+++ b/src/px.c
@@ -4,22 +4,22 @@
 PxCol pxbuf[PX_WIDTH * PX_HEIGHT] = {0};
 PxPal pxpal[256] = {
 	/* PICO-8 palette */
-	{0x00, 0x00, 0x00},
-	{0x1d, 0x2b, 0x53},
-	{0x7e, 0x25, 0x53},
-	{0x00, 0x87, 0x51},
-	{0xab, 0x52, 0x36},
-	{0x5f, 0x57, 0x4f},
-	{0xc2, 0xc3, 0xc7},
-	{0xff, 0xf1, 0xe8},
-	{0xff, 0x00, 0x4d},
-	{0xff, 0xa3, 0x00},
-	{0xff, 0xec, 0x27},
-	{0x00, 0xe4, 0x36},
-	{0x29, 0xad, 0xff},
-	{0x83, 0x76, 0x9c},
-	{0xff, 0x77, 0xa8},
-	{0xff, 0xcc, 0xaa},
+	{0x00, 0x00, 0x00, false},
+	{0x1d, 0x2b, 0x53, false},
+	{0x7e, 0x25, 0x53, false},
+	{0x00, 0x87, 0x51, false},
+	{0xab, 0x52, 0x36, false},
+	{0x5f, 0x57, 0x4f, false},
+	{0xc2, 0xc3, 0xc7, false},
+	{0xff, 0xf1, 0xe8, false},
+	{0xff, 0x00, 0x4d, false},
+	{0xff, 0xa3, 0x00, false},
+	{0xff, 0xec, 0x27, false},
+	{0x00, 0xe4, 0x36, false},
+	{0x29, 0xad, 0xff, false},
+	{0x83, 0x76, 0x9c, false},
+	{0xff, 0x77, 0xa8, false},
+	{0xff, 0xcc, 0xaa, false},
 };
 static struct {
 	int x;
@@ -90,8 +90,6 @@ _pxSpr(const PxSprArgs *args)
 	int h = (args->h < 0) ? (args->spr->h) : (args->h);
 	h = pxMin(h, args->spr->h - args->iy);
 
-	printf("%d %d\n", w, h);
-
 	for (int y = 0; y < h; y++) {
 		for (int x = 0; x < w; x++) {
 			const int dx = x + args->x;
@@ -99,12 +97,22 @@ _pxSpr(const PxSprArgs *args)
 			const int ix = x + args->ix;
 			const int iy = y + args->iy;
 			const PxCol c = args->spr->data[ix + iy * args->spr->w];
-			if (c)
+			if (!pxpal[c].t)
 				pxPset(dx, dy, c);
 		}
 	}
 }
 
+void
+_pxPalt(const PxPaltArgs *args)
+{
+	if (args->col < 0 || args->col > 255)
+		for (int i = 0; i < 256; i++)
+			pxpal[i].t = false;
+	else
+		pxpal[args->col].t = args->t;
+}
+
 int
 pxMin(int a, int b)
 {
diff --git a/src/px.h b/src/px.h
index 47ea705..e32f079 100644
--- a/src/px.h
+++ b/src/px.h
@@ -1,5 +1,6 @@
 #pragma once
 #include <stdint.h>
+#include <stdbool.h>
 
 enum {
 	PX_WIDTH = 128,
@@ -10,6 +11,7 @@ typedef uint8_t PxCol;
 
 typedef struct {
 	uint8_t r, g, b;
+	bool t; /* tranparency */
 } PxPal;
 
 typedef struct {
@@ -28,6 +30,12 @@ typedef struct {
 	int h;
 } PxSprArgs;
 
+typedef struct {
+	int _;
+	int col;
+	bool t;
+} PxPaltArgs;
+
 extern PxCol pxbuf[PX_WIDTH * PX_HEIGHT];
 extern PxPal pxpal[256];
 
@@ -54,6 +62,11 @@ PxCol pxPget(int x, int y);
 	.ix=0, .iy=0, .w=-1, .h=-1, ._=0, __VA_ARGS__})
 void _pxSpr(const PxSprArgs *args);
 
+/* Set palette tranparency. */
+#define pxPalt(...) _pxPalt(&(const PxPaltArgs){ \
+	.col=-1, .t=true, ._=0, __VA_ARGS__})
+void _pxPalt(const PxPaltArgs *args);
+
 /*** MATH ***/
 int pxMin(int a, int b);
 int pxMax(int a, int b);