add base code for windowing and opengl crt-shader.

1 files changed, 79 insertions, 0 deletions

diff --git a/base/render.c b/base/render.c
new file mode 100644
index 0000000..e7118d0
--- /dev/null
+++ b/base/render.c
@@ -0,0 +1,79 @@
+
+
+
+// Get pointer to where in the buffer to render RENDER_START(0,0) is top left
+#define RENDER_START(x, y) (state.display_buffer + ((y) << 11) + (x))
+
+// Center X Coordinate for Rendering
+#define CENTER_X(w) ((state.render_width - (w)) >> 1)
+
+/* [=]===^=[ update_render_position ]=================================================================^===[=] */
+static void update_render_position(void) {
+	state.render_x = (BUFFER_WIDTH - state.render_width) >> 1;
+	state.render_y = (BUFFER_HEIGHT - state.render_height) >> 1;
+	state.display_buffer = buffer + (state.render_y * BUFFER_WIDTH) + state.render_x;
+}
+
+/* [=]===^=[ change_resolution ]=================================================================^===[=] */
+static void change_resolution(uint32_t new_width, uint32_t new_height) {
+	if(new_width != state.render_width || new_height != state.render_height) {
+		state.render_width = new_width;
+		state.render_height = new_height;
+		update_render_position();
+		setup_render_target();
+	}
+}
+
+/* [=]===^=[ clear_buffer ]=================================================================^===[=] */
+__attribute__((always_inline, hot))
+static inline void clear_buffer(void) {
+	PROFILE_FUNCTION();
+	uint32_t * restrict dst = RENDER_START(0, 0);
+
+	for(uint32_t i = 0; i < state.render_height; i++) {
+		memset(dst, 0, state.render_width * 4);
+		dst += BUFFER_WIDTH;
+	}
+}
+
+/* [=]===^=[ set_decay ]=================================================================^===[=] */
+static uint16_t _old_weight;
+static uint16_t _new_weight;
+static void set_decay(uint16_t old_weight) {
+	_old_weight = old_weight ? (old_weight > 256 ? 256 : old_weight) : 0;
+	_new_weight = 256 - old_weight;
+}
+
+/* [=]===^=[ apply_phosphor_decay ]=================================================================^===[=] */
+__attribute__((always_inline, hot))
+static inline void apply_phosphor_decay(void) {
+	PROFILE_FUNCTION();
+	__m256i old_weight = _mm256_set1_epi16(_old_weight);
+	__m256i new_weight = _mm256_set1_epi16(_new_weight);
+	__m128i alpha_mask = _mm_set1_epi32(0x000000ff);
+	uint32_t render_width = state.render_width;
+	uint32_t render_height = state.render_height;
+	uint32_t * restrict src = RENDER_START(0, 0);
+	uint32_t * restrict dst = display_buffer;
+
+	for(uint32_t y = 0; y < render_height; ++y, src += BUFFER_WIDTH, dst += render_width) {
+		for(uint32_t x = 0; x < render_width; x += 4) {
+			_mm_prefetch((char*)&src[x + 2 * BUFFER_WIDTH], _MM_HINT_T0);
+			_mm_prefetch((char*)&dst[x + 2 * render_width], _MM_HINT_T0);
+
+			__m128i new_pixels = _mm_loadu_si128((__m128i*)&src[x]);
+			__m128i old_pixels = _mm_loadu_si128((__m128i*)&dst[x]);
+
+			__m256i old_lo = _mm256_cvtepu8_epi16(old_pixels);
+			__m256i new_lo = _mm256_cvtepu8_epi16(new_pixels);
+
+			__m256i blended = _mm256_adds_epu16(_mm256_mullo_epi16(old_lo, old_weight), _mm256_mullo_epi16(new_lo, new_weight));
+			blended = _mm256_srli_epi16(blended, 8);
+
+			__m128i final_pixels = _mm_packus_epi16(_mm256_castsi256_si128(blended), _mm256_extracti128_si256(blended, 1));
+			final_pixels = _mm_or_si128(final_pixels, _mm_and_si128(old_pixels, alpha_mask));
+			_mm_storeu_si128((__m128i*)&dst[x], final_pixels);
+		}
+	}
+}
+