Added setpixel(x,y) with examples

README.md

@@ -57,6 +57,7 @@ Drawing functions:
 * text(x,y,string): print the specified text at x,y using a bitmap font.
 * triangle(x1,y1,x2,y2,x3,y3): draw a triangle with the specified vertex.
 * getpixel(x,y): return the red,gree,blue value of the specified pixel.
+* setpixel(x,y): draw a pixel at x,y.
 * sprite(file,x,y,[rotation],[antialiasing]): draw sprite at coordinates with the specified rotation (in degrees, default 0) and antialiasing (default false).
 
 Control functions:

examples/astropixel.lua

@@ -0,0 +1,33 @@
+-- astropixel - getpixel/setpixel demo / k255 | 3x /
+
+function setup()
+    px,py=WIDTH/2,HEIGHT/2
+    dpx,dpy=4,4
+    sx,sy={},{}
+    sn=1024
+    for i=1,sn do
+        sx[i],sy[i]=math.random(1,WIDTH),math.random(1,HEIGHT)
+    end
+    pc,sc={ 255,255,255,1 },{ 255,0,255,1 }
+    tick=0
+    setFPS(60)
+end
+
+function draw()
+    tick=tick+1
+    fill(0,0,0,0.05)
+    rect(0,0,WIDTH,HEIGHT)
+    fill(unpack(sc))
+    for i=1,sn do
+        if tick%60==0 and math.random(0,10)==10 then
+          ellipse(sx[i],sy[i],2,2)
+        end
+        ellipse(sx[i],sy[i],1,1)
+    end
+    fill(unpack(pc))
+    if getpixel(px,py) == unpack(sc) then
+        dpx,dpy=math.random(-10,10)/5,math.random(-10,10)/5
+    end
+    setpixel(px,py)
+    px,py=(px+dpx)%WIDTH,(py+dpy)%HEIGHT
+end

examples/pixels.lua

@@ -0,0 +1,19 @@
+-- pixels - setpixel demo / k255 | 3x /
+
+function setup()
+    tick=0
+    d=1000
+    s=50
+    rgba={ 255,255,255,.75 }
+end
+
+function draw()
+    tick=tick+1
+    fill(unpack(rgba))
+    if tick%s==0 then
+        rgba[math.random(1,3)] = math.random(0,255)
+    end
+    for i=0,d,1 do
+      setpixel(math.random(0,WIDTH),math.random(0,HEIGHT))
+    end
+end

load81.c

@@ -252,6 +252,16 @@ int getpixelBinding(lua_State *L) {
     return 3;
 }
 
+int setpixelBinding(lua_State *L) {
+    int x, y;
+
+    x = lua_tonumber(L,-2);
+    y = lua_tonumber(L,-1);
+
+    setPixelWithAlpha(l81.fb,x,y,l81.r,l81.g,l81.b,l81.alpha);
+    return 0;
+}
+
 int spriteBinding(lua_State *L) {
     const char *filename;
     int x, y, angle, antialiasing;
@@ -491,6 +501,8 @@ void resetProgram(void) {
     lua_setglobal(l81.L,"setFPS");
     lua_pushcfunction(l81.L,getpixelBinding);
     lua_setglobal(l81.L,"getpixel");
+    lua_pushcfunction(l81.L,setpixelBinding);
+    lua_setglobal(l81.L,"setpixel");
     lua_pushcfunction(l81.L,spriteBinding);
     lua_setglobal(l81.L,"sprite");