Re-work triangles and make a generic version for it.

src/helpers/pax_dh_generic_rect.h

@@ -1,3 +1,26 @@
+/*
+	MIT License
+
+	Copyright (c) 2021-2023 Julian Scheffers
+
+	Permission is hereby granted, free of charge, to any person obtaining a copy
+	of this software and associated documentation files (the "Software"), to deal
+	in the Software without restriction, including without limitation the rights
+	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+	copies of the Software, and to permit persons to whom the Software is
+	furnished to do so, subject to the following conditions:
+
+	The above copyright notice and this permission notice shall be included in all
+	copies or substantial portions of the Software.
+
+	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+	SOFTWARE.
+*/
 
 #include "pax_internal.h"
 

src/helpers/pax_dh_generic_tri.h

@@ -0,0 +1,312 @@
+/*
+	MIT License
+
+	Copyright (c) 2021-2023 Julian Scheffers
+
+	Permission is hereby granted, free of charge, to any person obtaining a copy
+	of this software and associated documentation files (the "Software"), to deal
+	in the Software without restriction, including without limitation the rights
+	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+	copies of the Software, and to permit persons to whom the Software is
+	furnished to do so, subject to the following conditions:
+
+	The above copyright notice and this permission notice shall be included in all
+	copies or substantial portions of the Software.
+
+	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+	SOFTWARE.
+*/
+
+#include "pax_internal.h"
+
+#ifdef PDHG_NAME
+
+#if defined(PDHG_SHADED) && !defined(PDHG_IGNORE_UV)
+#define PDHG_NORMAL_UV
+#endif
+
+#ifdef PDHG_MCR
+#define PDHG_INCREMENT 2
+#else
+#define PDHG_INCREMENT 1
+#endif
+
+#if !defined(PDHG_SHADED) && defined(PDHG_IGNORE_UV)
+#error "Cannot define `PDHG_IGNORE_UV` without `PDHG_SHADED`."
+#endif
+
+#ifdef PDHG_RESTRICT_UV
+#error "Cannot define `PDHG_RESTRICT_UV` for triangles."
+#endif
+
+#if defined(PDHG_IGNORE_UV) && defined(PDHG_MCR)
+#define PDHG_TRAPEZOID_NAME paxmcr_trapezoid_shaded_nouv
+#elif defined(PDHG_SHADED) && defined(PDHG_MCR)
+#define PDHG_TRAPEZOID_NAME paxmcr_trapezoid_shaded
+#elif defined(PDHG_IGNORE_UV)
+#define PDHG_TRAPEZOID_NAME pax_trapezoid_shaded_nouv
+#elif defined(PDHG_SHADED)
+#define PDHG_TRAPEZOID_NAME pax_trapezoid_shaded
+#elif defined(PDHG_MCR)
+#define PDHG_TRAPEZOID_NAME paxmcr_trapezoid_unshaded
+#else
+#define PDHG_TRAPEZOID_NAME pax_trapezoid_unshaded
+#endif
+
+
+
+// Trapezoid function, a triangle is made out of two of these.
+// Assumes y0 < y1.
+static void PDHG_TRAPEZOID_NAME(
+#ifdef PDHG_MCR
+		bool odd_scanline,
+#endif
+		pax_buf_t *buf, pax_col_t color,
+#ifdef PDHG_SHADED
+		const pax_shader_t *shader,
+#endif
+		float x0a, float x0b, float y0, float x1a, float x1b, float y1
+#ifdef PDHG_NORMAL_UV
+		, float u0a, float v0a, float u0b, float v0b, float u1a, float v1a, float u1b, float v1b
+#endif
+		) {
+
+	#ifdef PDHG_SHADED
+	// Get shader context.
+	pax_shader_ctx_t shader_ctx = pax_get_shader_ctx(buf, color, shader);
+	if (shader_ctx.skip) return;
+	pax_col_conv_t buf2col = PAX_IS_PALETTE(buf->type) ? pax_col_conv_dummy : buf->buf2col;
+	#else
+	// Get pixel setter.
+	pax_index_setter_t setter = pax_get_setter(buf, &color, NULL);
+	if (!setter) return;
+	#endif
+
+	// Determine vertical bounds.
+	int iy0 = y0 + 0.5;
+	int iy1 = y1 + 0.5;
+	if (iy0 >= iy1) return;
+
+	// Sort points by X.
+	if (x0a > x0b || x1a > x1b) {
+		PAX_SWAP(float, x0a, x0b);
+		PAX_SWAP(float, x1a, x1b);
+		#ifdef PDHG_NORMAL_UV
+		PAX_SWAP(float, u0a, u0b);
+		PAX_SWAP(float, u1a, u1b);
+		PAX_SWAP(float, v0a, v0b);
+		PAX_SWAP(float, v1a, v1b);
+		#endif
+	}
+
+	// Clip: Y axis.
+	if (iy0 < buf->clip.y) {
+		iy0 = buf->clip.y;
+	}
+	if (iy0 >= buf->clip.y + buf->clip.h) {
+		return;
+	}
+	if (iy1 < buf->clip.y) {
+		return;
+	}
+	if (iy1 >= buf->clip.y + buf->clip.h) {
+		iy1 = buf->clip.y + buf->clip.h - 1;
+	}
+
+	#ifdef PDHG_MCR
+	// Snap y to correct scanline.
+	if ((iy0 & 1) != odd_scanline) {
+		iy0 ++;
+	}
+	#endif
+
+	// Determine X deltas.
+	float x0a_x1a_dx = (x1a - x0a) / (y1 - y0);
+	float x0b_x1b_dx = (x1b - x0b) / (y1 - y0);
+
+	#ifdef PDHG_NORMAL_UV
+	// Determine UV deltas.
+	float u0a_u1a_du = (u1a - u0a) / (y1 - y0);
+	float u0b_u1b_du = (u1b - u0b) / (y1 - y0);
+	float v0a_v1a_dv = (v1a - v0a) / (y1 - y0);
+	float v0b_v1b_dv = (v1b - v0b) / (y1 - y0);
+	#endif
+
+	// Initial X interpolation.
+	float coeff = (iy0 + 0.5f) - y0;
+	float x_a = x0a + x0a_x1a_dx * coeff;
+	float x_b = x0b + x0b_x1b_dx * coeff;
+
+	#ifdef PDHG_NORMAL_UV
+	// Initial UV interpolation.
+	float u_a = u0a + u0a_u1a_du * coeff;
+	float u_b = u0b + u0b_u1b_du * coeff;
+	float v_a = v0a + v0a_v1a_dv * coeff;
+	float v_b = v0b + v0b_v1b_dv * coeff;
+	#endif
+
+	// Vertical drawing loop.
+	int delta = buf->width * iy0;
+	for (int y = iy0; y < iy1; y += PDHG_INCREMENT) {
+		int ixa = x_a + 0.5, ixb = x_b + 0.5;
+
+		// Clip: X axis.
+		if (ixa < buf->clip.x) {
+			ixa = buf->clip.x;
+		}
+		if (ixa > buf->clip.x + buf->clip.w) {
+			ixa = buf->clip.x + buf->clip.w;
+		}
+		if (ixb < buf->clip.x) {
+			ixb = buf->clip.x;
+		}
+		if (ixb > buf->clip.x + buf->clip.w) {
+			ixb = buf->clip.x + buf->clip.w;
+		}
+
+		#ifdef PDHG_NORMAL_UV
+		// Determine UV deltas.
+		float du = (u_b - u_a) / (x_b - x_a);
+		float dv = (v_b - v_a) / (x_b - x_a);
+
+		// Interpolate UV.
+		coeff = (ixa + 0.5) - x_a;
+		float u = u_a + du * coeff;
+		float v = v_a + dv * coeff;
+		#endif
+
+		// Horizontal drawing loop.
+		for (int x = ixa; x < ixb; x ++) {
+			#ifdef PDHG_NORMAL_UV
+			// Apply the shader,
+			pax_col_t result = (shader_ctx.callback)(color, shader_ctx.do_getter ? buf2col(buf, buf->getter(buf, x+delta)) : 0, x, y, u, v, shader_ctx.callback_args);
+			// And simply merge colors accordingly.
+			pax_set_index_conv(buf, result, x+delta);
+			u += du;
+			v += dv;
+			#elif defined(PDHG_SHADED)
+			// Apply the shader,
+			pax_col_t result = (shader_ctx.callback)(color, shader_ctx.do_getter ? buf2col(buf, buf->getter(buf, x+delta)) : 0, x, y, 0, 0, shader_ctx.callback_args);
+			// And simply merge colors accordingly.
+			pax_set_index_conv(buf, result, x+delta);
+			#else
+			// And simply merge colors accordingly.
+			setter(buf, color, x+delta);
+			#endif
+		}
+
+		#ifdef PDHG_NORMAL_UV
+		// Interpolate UVs.
+		u_a += PDHG_INCREMENT*u0a_u1a_du;
+		u_b += PDHG_INCREMENT*u0b_u1b_du;
+		v_a += PDHG_INCREMENT*v0a_v1a_dv;
+		v_b += PDHG_INCREMENT*v0b_v1b_dv;
+		#endif
+
+		// Interpolate X.
+		x_a += PDHG_INCREMENT*x0a_x1a_dx;
+		x_b += PDHG_INCREMENT*x0b_x1b_dx;
+
+		delta += PDHG_INCREMENT*buf->width;
+	}
+}
+
+
+
+// Generic triangle drawing code, assuming some defines are made.
+#ifdef PDHG_STATIC
+static
+#endif
+void PDHG_NAME (
+#ifdef PDHG_MCR
+		bool odd_scanline,
+#endif
+		pax_buf_t *buf, pax_col_t color,
+#ifdef PDHG_SHADED
+		const pax_shader_t *shader,
+#endif
+		float x0, float y0, float x1, float y1, float x2, float y2
+#ifdef PDHG_NORMAL_UV
+		, float u0, float v0, float u1, float v1, float u2, float v2
+#endif
+		) {
+
+	// Sort points by height.
+	if (y1 < y0) {
+		PAX_SWAP_POINTS(x0, y0, x1, y1);
+		#ifdef PDHG_NORMAL_UV
+		PAX_SWAP_POINTS(u0, v0, u1, v1);
+		#endif
+	}
+	if (y2 < y0) {
+		PAX_SWAP_POINTS(x0, y0, x2, y2);
+		#ifdef PDHG_NORMAL_UV
+		PAX_SWAP_POINTS(u0, v0, u2, v2);
+		#endif
+	}
+	if (y2 < y1) {
+		PAX_SWAP_POINTS(x1, y1, x2, y2);
+		#ifdef PDHG_NORMAL_UV
+		PAX_SWAP_POINTS(u1, v1, u2, v2);
+		#endif
+	}
+
+	// Interpolate coordinates.
+	float coeff = (y1 - y0) / (y2 - y0);
+	float x1b = x0 + (x2 - x0) * coeff;
+	#ifdef PDHG_NORMAL_UV
+	float u1b = u0 + (u2 - u0) * coeff;
+	float v1b = v0 + (v2 - v0) * coeff;
+	#endif
+
+	// Top half.
+	PDHG_TRAPEZOID_NAME(
+		#ifdef PDHG_MCR
+		odd_scanline,
+		#endif
+		buf, color,
+		#ifdef PDHG_SHADED
+		shader,
+		#endif
+		x0, x0, y0, x1, x1b, y1
+		#ifdef PDHG_NORMAL_UV
+		, u0, v0, u0, v0, u1, v1, u1b, v1b
+		#endif
+	);
+	// Bottom half.
+	PDHG_TRAPEZOID_NAME(
+		#ifdef PDHG_MCR
+		odd_scanline,
+		#endif
+		buf, color,
+		#ifdef PDHG_SHADED
+		shader,
+		#endif
+		x1, x1b, y1, x2, x2, y2
+		#ifdef PDHG_NORMAL_UV
+		, u1, u1b, v1, v1b, u2, v2, u2, v2
+		#endif
+	);
+}
+
+
+
+#endif // PDHG_NAME
+
+// Clean up macros.
+#undef PDHG_INCREMENT
+#undef PDHG_NORMAL_UV
+#undef PDHG_TRAPEZOID_NAME
+
+// Clean up parameter macros.
+#undef PDHG_STATIC
+#undef PDHG_NAME
+#undef PDHG_SHADED
+#undef PDHG_MCR
+#undef PDHG_IGNORE_UV
+#undef PDHG_RESTRICT_UV