lol

ugui.c

@@ -0,0 +1,217 @@
+#include <stdlib.h>
+#include <string.h>
+#include <err.h>
+#include <errno.h>
+
+#include "ugui.h"
+
+#define SALT         0xbabb0cac
+#define DEF_SCALE    1.0
+#define DEF_DPI      96.0
+#define E_STACK_STEP (1024 * 128)
+
+#define TO_PPM(dpi, scale) (dpi * scale * 0.03937008)
+
+// https://en.wikipedia.org/wiki/Jenkins_hash_function
+unsigned int hash(void *data, unsigned int size)
+{
+	if (!size)
+		return 0;
+	unsigned int hash = SALT;
+	unsigned char *v = (unsigned char *)data;
+
+	for (; size; size--) {
+		hash += v[size-1];
+		hash += hash << 10;
+		hash ^= hash >> 6;
+	}
+	hash += hash << 3;
+  	hash ^= hash >> 11;
+  	hash += hash << 15;
+	
+	return hash;
+}
+
+
+static void grow_stack(ug_ctx_t *ctx)
+{
+	if (!ctx)
+		err(EXIT_FAILURE, "__FUNCTION__:" "Cannot grow null context");
+	ctx->e_size += E_STACK_STEP;
+	ctx->e_stack = realloc(ctx->e_stack, ctx->e_size);
+	if (!ctx->e_stack)
+		err(errno, "__FUNCTION__:" "Could not grow stack: %s", strerror(errno));
+}
+
+
+// creates a new context, fills with default values, ctx is ready for ug_start()
+ug_ctx_t *ug_new_ctx(void)
+{
+	ug_ctx_t *ctx = malloc(sizeof(ug_ctx_t));
+	if (!ctx)
+		err(errno, "__FUNCTION__:" "Could not allocate context: %s", strerror(errno));
+	memset(ctx, 0, sizeof(ug_ctx_t));
+
+	ctx->scale     = DEF_SCALE;
+	ctx->dpi       = DEF_DPI;
+	ctx->ppm       = TO_PPM(DEF_SCALE, DEF_DPI);
+	
+	return ctx;
+}
+
+
+void ug_free_ctx(ug_ctx_t *ctx)
+{
+	if (!ctx) {
+		warn("__FUNCTION__:" "Trying to free a null context");
+		return;
+	}
+	
+	if (!ctx->e_stack) {
+		warn("__FUNCTION__:" "Context has null element stack");
+		return;
+	}
+
+	free(ctx->e_stack);
+	free(ctx);
+}
+
+
+// updates the context with user information
+int ug_update_ctx(ug_ctx_t *ctx,
+                  unsigned int window_id,
+	          float scale,
+	          float dpi,
+	          float ppm
+	         )
+{
+	if (!ctx)
+		return -1;
+	ctx->window_id = window_id;
+
+	if (scale)
+		ctx->scale = scale;
+	if (dpi)
+		ctx->dpi = dpi;
+	if (!ppm)
+		ctx->ppm = TO_PPM(ctx->dpi, ctx->scale);
+	else
+		ctx->ppm = ppm;
+
+	return 0;
+}
+
+
+/*=============================================================================*
+ *                              INPUT FUNCTIONS                                *
+ *=============================================================================*/
+
+#define TEST_CTX(ctx) {                                                \
+	if (!ctx) {                                                    \
+		warn("__FUNCTION__:" "trying to use a null context");  \
+		return;                                                \
+	}                                                              \
+}
+
+void ug_input_mousemove(ug_ctx_t *ctx, int x, int y)
+{
+	TEST_CTX(ctx);
+	ctx->mouse.pos = (struct ug_vec2){ .x = x, .y = y };
+}
+
+void ug_input_mousedown(ug_ctx_t *ctx, int x, int y, unsigned char btn)
+{
+	TEST_CTX(ctx);
+	ug_input_mousemove(ctx, x, y);
+	ctx->mouse.down_mask |= btn;
+	ctx->mouse.press_mask |= btn;
+}
+
+
+void ug_input_mouseup(ug_ctx_t *ctx, int x, int y, unsigned char btn)
+{
+	TEST_CTX(ctx);
+	ug_input_mousemove(ctx, x, y);
+	ctx->mouse.down_mask &= ~btn;
+}
+
+
+void ug_input_scroll(ug_ctx_t *ctx, int x, int y)
+{
+	TEST_CTX(ctx);
+	ctx->mouse.scroll_delta.x += x;
+	ctx->mouse.scroll_delta.y += y;
+}
+
+
+void ug_input_keydown(ug_ctx_t *ctx, int key)
+{
+	TEST_CTX(ctx);
+	ctx->key.down_mask |= key;
+	ctx->key.press_mask |= key;
+}
+
+
+void ug_input_keyup(ug_ctx_t *ctx, int key)
+{
+	TEST_CTX(ctx);
+	ctx->key.down_mask &= ~key;
+}
+
+
+// append in input text
+void ug_input_text(ug_ctx_t *ctx, const char *text)
+{
+	TEST_CTX(ctx);
+	int size = strlen(ctx->input_text);
+	int len  = strlen(text);
+	if ((unsigned long)(size+len) >= sizeof(ctx->input_text)) {
+		warn("__FUNCTION__" "Input text exceeds context buffer");
+		return;
+	}
+	memcpy(ctx->input_text + size, text, len);
+}
+
+
+/*=============================================================================*
+ *                              BEGIN AND END                                  *
+ *=============================================================================*/
+
+#undef TEST_CTX
+#define TEST_CTX(ctx) {                                                \
+	if (!ctx) {                                                    \
+		warn("__FUNCTION__:" "trying to use a null context");  \
+		return -1;                                             \
+	}                                                              \
+}
+
+int ug_begin(ug_ctx_t *ctx)
+{
+	// it is the beginning of a new frame
+	TEST_CTX(ctx);
+
+	// reset the command stack
+	ctx->e_idx = 0;
+	// next frame
+	ctx->frame++;
+	// update the mouse delta
+	ctx->mouse.delta.x = ctx->mouse.pos.x - ctx->mouse.last_pos.x;
+	ctx->mouse.delta.y = ctx->mouse.pos.y - ctx->mouse.last_pos.y;
+	// TODO: other stuff
+	return 0;
+}
+
+
+int ug_end(ug_ctx_t *ctx)
+{
+	// end of a frame, check that all went well
+	TEST_CTX(ctx);
+
+	// reset the inputs
+	ctx->mouse.press_mask   = 0;
+	ctx->mouse.scroll_delta = (struct ug_vec2){0};
+	ctx->mouse.last_pos     = ctx->mouse.pos;
+	ctx->key.press_mask     = 0;
+	ctx->input_text[0]      = '\0';
+	return 0;
+}