initial commit

2026-07-18 20:34:55 +02:00
commit 59ad004c96
474 changed files with 226635 additions and 0 deletions
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+#include <string.h>
+#include <c64/vic.h>
+#include <c64/memmap.h>
+#include <conio.h>
+#include <math.h>
+
+// Address of hires buffer and color buffers
+#define Screen	((char *)0xe000)
+#define Color1	((char *)0xc800)
+#define Color2	((char *)0xd800)
+
+// Bit patterns for two different color pairs and eight shades
+byte	colors[2][17] = 
+{
+	{0x00, 
+	 0x44, 0x44, 0x55, 0x55, 0xdd, 0xdd, 0xff, 0xff,
+	 0x88, 0x88, 0xaa, 0xaa, 0xee, 0xee, 0xff, 0xff,
+	},
+	{0x00, 
+	 0x00, 0x11, 0x11, 0x55, 0x55, 0x77, 0x77, 0xff,
+	 0x00, 0x22, 0x22, 0xaa, 0xaa, 0xbb, 0xbb, 0xff,
+	}
+};
+
+// Fill a vertical line x from py to ty with color c
+void VLine(int x, int py, int ty, char c)
+{
+	// Clip boundaries
+	if (py < 0)
+		py = 0;
+	if (ty > 100)
+		ty = 100;
+
+	// Check if there are pixel to draw
+	if (py < ty)
+	{
+		// Calculate top address and mask
+		char	mask = 0xc0 >> (2 * (x & 3));
+		char	* dp = Screen + 320 * (py >> 2) + 2 * (py & 3) + 2 * (x & ~3);
+
+		// Get the two color patterns
+		char c0 = colors[0][c] & mask, c1 = colors[1][c] & mask;
+
+		// Invert mask to cover the unchanged portion
+		mask = ~mask;
+
+		// Loop over all pixels
+		char h = ty - py;
+		while (h)
+		{
+			// Apply color to memory
+			dp[0] = (dp[0] & mask) | c0; 
+			dp[1] = (dp[1] & mask) | c1; 
+
+			// Two pixel lines down
+			dp += 2;
+			if (!((int)dp & 7))
+				dp += 312;
+
+			h--;
+		}
+	}
+}
+
+// Iterate up to 32 iterations and return a smoothed height
+float iter(float xz, float yz)
+{
+	float	x = 0.0, y = 0.0, r;
+	int		i;
+	for(i=0; i<32; i++)
+	{
+		r = x * x + y * y;
+		if (r > 64.0) break;
+				
+		float	xt = x * x - y * y + xz;
+		y = 2 * x * y + yz;
+		x = xt;
+	}
+	
+	
+	if (i == 32)
+		return 32;
+	else
+		return i - log(log(r)/log(64.0))/log(2.0);
+}
+
+// Calculate light with given new and old heights
+int light(float hl, float hu, float h)
+{
+	float	dx = h - hl, dz = h - hu, dy = 0.1;
+	
+	float	dd = sqrt(dx * dx + dy * dy + dz * dz);
+	int		ni = (int)floor((-2 * dx + dy + dz) / dd * 0.408 * 8);
+	if (ni < 0) ni = 0; else if (ni > 7) ni = 7;
+
+	return ni;
+}
+
+int main(void)
+{
+	// Install the IRQ trampoline
+	mmap_trampoline();
+
+	// Turn of the kernal ROM
+	mmap_set(MMAP_NO_ROM);
+
+	// Switch VIC into multicolor bitmap mode
+	vic_setmode(VICM_HIRES_MC, Color1, Screen);
+
+	// Clear the screen and set the colors
+	vic.color_back = 0x00;
+	vic.color_border = 0x00;
+
+	memset(Screen, 0, 8000);
+	memset(Color1, 0x26, 1000);
+	memset(Color2, 0x0f, 1000);
+
+	// Height of previous row, needed for lighting	
+	float	hl[200];
+	
+	// Rotation of complex plane
+	float	w = -0.7;
+	float	co = cos(w), si = sin(w);
+	
+	// Loop from left to right
+	for(int x=-1; x<160; x+= 1)
+	{
+		// Loop from far to nead
+		int	py = 20;
+		float	hu = 0;
+		for(int y=1; y<200; y+= 1)
+		{
+			// Inverse 3D projection
+			float fz = 2.0 / (float)y;
+			float fx = (float)(x - 80) * fz / 100.0;
+			
+			float	mz = fz * 100.0 - 3.0, mx = fx * 100.0;
+
+			// Rotation of the plane
+			float	rx = mx * co - mz * si, rz = mx * si + mz * co;
+			float	dp = iter(rx, rz);
+			float	v = 2 * dp;
+			if (v < 1.0) v = 1.0;
+			
+			float	fy = 5.0 * pow(2.0, - v * 0.4);
+			
+			// Calculate light
+			int		ni = light(hl[y], hu, fy);
+
+			// Update left column
+			hl[y] = fy;
+			hu = fy;
+
+			// Forward 3D projection
+			int		ty = 20 + y / 2 + (int)(floor(fy / fz));
+
+			
+			// color of pixel
+			int		c;
+			if (dp != 32) 
+				c = 1 + ni + 8 * ((int)floor(dp) & 1);
+			else
+				c = 0;
+
+			// Draw line if not dummy left row
+			if (x >= 0)
+				VLine(x, py, ty, c);
+
+			py = ty;
+		}
+	}
+
+	// Re-enable the kernal
+	mmap_set(MMAP_NO_BASIC);
+
+	// Wait for key press
+	getch();	
+
+	// Restore VIC state
+	vic_setmode(VICM_TEXT, (char *)0x0400, (char *)0x1000);
+	
+	return 0;
+}