/**
* @name context_2d_setClip
* @brief sets the clipping rectangle on the given context
* @param ctx - (context_2d *) context to set the clipping rectangle on
* @param clip - (rect_2d) the clipping rectangle
* @retval NONE
*/
void context_2d_setClip(context_2d *ctx, rect_2d clip) {
matrix_3x3 *modelView = GET_MODEL_VIEW_MATRIX(ctx);
// LOG("setClip: %f %f %f %f", clip.x, clip.y, clip.width, clip.height);
// TODO: clipping with rectangles doesn't work so great with rotated or scaled coordinates...
float x1, y1, x2, y2;
matrix_3x3_multiply(modelView, clip.x, clip.y, &x1, &y1);
matrix_3x3_multiply(modelView, clip.x + clip.width, clip.y + clip.height, &x2, &y2);
clip.x = x1;
clip.y = y1;
clip.width = x2 - x1;
clip.height = y2 - y1;
int i = ctx->mvp - 1;
rect_2d ctx_clip;
ctx_clip.x = ctx->clipStack[i].x;
ctx_clip.y = ctx->clipStack[i].y;
ctx_clip.width = ctx->clipStack[i].width;
ctx_clip.height = ctx->clipStack[i].height;
//flip the y to be back at top left for easier readability of intersection testing
if (ctx->on_screen && clip.height > 0) {
ctx_clip.y = -ctx_clip.y + ctx->canvas->framebuffer_height + ctx->canvas->framebuffer_offset_bottom - ctx_clip.height;
}
//width = -1 if view is not clipping so ignore it
if (ctx_clip.width > -1) {
//set clip rect to empty if the clip coming in is outside of the clip stack's top clipping rect
if (clip.x >= ctx_clip.x + ctx_clip.width || clip.x + clip.width <= ctx_clip.x ||
clip.y >= ctx_clip.y + ctx_clip.height || clip.y + clip.height <= ctx_clip.y) {
clip.x = clip.y = clip.height = clip.width = 0;
} else {
clip.x = ctx_clip.x > x1 ? ctx_clip.x : x1;
clip.y = ctx_clip.y > y1 ? ctx_clip.y : y1;
clip.width = (ctx_clip.x + ctx_clip.width < x2 ? ctx_clip.x + ctx_clip.width : x2) - clip.x;
clip.height = (ctx_clip.y + ctx_clip.height < y2 ? ctx_clip.y + ctx_clip.height : y2) - clip.y;
}
}
// scissor is with respect to lower-left corner
// activeFrameBufferHeight is the height of the off-screen buffer
// activeFrameBufferOffsetBottom -- the viewport actually goes past the bottom of the texture
// to the nearest power of two, so when we convert to y-coordinates from the lower-left viewport
// corner, we need to add the offsetBottom to get to the bottom of the viewable texture
if (ctx->on_screen && clip.height > 0) {
clip.y = ctx->canvas->framebuffer_height - (clip.height + clip.y) + ctx->canvas->framebuffer_offset_bottom;
}
rect_2d bounds = {clip.x, clip.y, clip.width, clip.height};
if (rect_2d_equals(GET_CLIPPING_BOUNDS(ctx), &bounds)) {
return;
}
*GET_CLIPPING_BOUNDS(ctx) = bounds;
enable_scissor(ctx);
}
/**
* @name context_2d_restore
* @brief pop's off the global properties stacks and resets glScissors
* @param ctx - (context_2d *) context to restore
* @retval NONE
*/
void context_2d_restore(context_2d *ctx) {
ctx->mvp--;
if (!rect_2d_equals(&ctx->clipStack[ctx->mvp], &ctx->clipStack[ctx->mvp + 1])) {
if (ctx->clipStack[ctx->mvp].width == -1) {
disable_scissor(ctx);
} else {
enable_scissor(ctx);
}
}
}
/**
* @name enable_scissor
* @brief enables the use of glScissors using proprties from the given context
* @param ctx - (context_2d *)
* @retval NONE
*/
void enable_scissor(context_2d *ctx) {
rect_2d *bounds = GET_CLIPPING_BOUNDS(ctx);
if (rect_2d_equals(&last_scissor_rect, bounds)) {
return;
}
draw_textures_flush();
last_scissor_rect.x = bounds->x;
last_scissor_rect.y = bounds->y;
last_scissor_rect.width = bounds->width;
last_scissor_rect.height = bounds->height;
GLTRACE(glScissor((int) bounds->x, (int) bounds->y, (int) bounds->width, (int) bounds->height));
GLTRACE(glEnable(GL_SCISSOR_TEST));
}
/**
* @name context_2d_restore
* @brief pop's off the global properties stacks and resets glScissors
* @param ctx - (context_2d *) context to restore
* @retval NONE
*/
void context_2d_restore(context_2d *ctx) {
int mvp = ctx->mvp - 1;
// If stack still has items on it,
if (mvp >= 0) {
ctx->mvp = mvp;
if (!rect_2d_equals(&ctx->clipStack[mvp], &ctx->clipStack[mvp + 1])) {
if (ctx->clipStack[mvp].width == -1) {
disable_scissor(ctx);
} else {
enable_scissor(ctx);
}
}
}
}
/**
* @name context_2d_setClip
* @brief sets the clipping rectangle on the given context
* @param ctx - (context_2d *) context to set the clipping rectangle on
* @param clip - (rect_2d) the clipping rectangle
* @retval NONE
*/
void context_2d_setClip(context_2d *ctx, rect_2d clip) {
matrix_3x3 *modelView = GET_MODEL_VIEW_MATRIX(ctx);
#ifdef MATRIX_3x3_ALLOW_SKEW
// TODO: Can this be done more efficiently?
float clip_x, clip_y, clip_w, clip_h;
float x1, y1, x2, y2, x3, y3, x4, y4;
matrix_3x3_multiply(modelView, clip.x, clip.y, &x1, &y1);
matrix_3x3_multiply(modelView, clip.x + clip.width, clip.y + clip.height, &x2, &y2);
matrix_3x3_multiply(modelView, clip.x, clip.y + clip.height, &x3, &y3);
matrix_3x3_multiply(modelView, clip.x + clip.width, clip.y, &x4, &y4);
clip_x = x1;
if (x2 < clip_x) {
clip_x = x2;
}
if (x3 < clip_x) {
clip_x = x3;
}
if (x4 < clip_x) {
clip_x = x4;
}
clip_y = y1;
if (y2 < clip_y) {
clip_y = y2;
}
if (y3 < clip_y) {
clip_y = y3;
}
if (y4 < clip_y) {
clip_y = y4;
}
clip_w = x1;
if (x2 > clip_w) {
clip_w = x2;
}
if (x3 > clip_w) {
clip_w = x3;
}
if (x4 > clip_w) {
clip_w = x4;
}
clip_h = y1;
if (y2 > clip_h) {
clip_h = y2;
}
if (y3 > clip_h) {
clip_h = y3;
}
if (y4 > clip_h) {
clip_h = y4;
}
clip.x = clip_x;
clip.y = clip_y;
clip.width = clip_w - clip_x;
clip.height = clip_h - clip_y;
#else
float clip0x = clip.x, clip0y = clip.y;
float clip1x = clip0x + clip.width, clip1y = clip0y + clip.height;
// float x1, y1, x2, y2, x3, y3, x4, y4;
// x1 = clip0x * modelView->m00 + clip0y * modelView->m01 + modelView->m02;
// y1 = clip0x * modelView->m10 + clip0y * modelView->m11 + modelView->m12;
// x2 = clip1x * modelView->m00 + clip0y * modelView->m01 + modelView->m02;
// y2 = clip1x * modelView->m10 + clip0y * modelView->m11 + modelView->m12;
// x3 = clip1x * modelView->m00 + clip1y * modelView->m01 + modelView->m02;
// y3 = clip1x * modelView->m10 + clip1y * modelView->m11 + modelView->m12;
// x4 = clip0x * modelView->m00 + clip1y * modelView->m01 + modelView->m02;
// y4 = clip0x * modelView->m10 + clip1y * modelView->m11 + modelView->m12;
float m00 = modelView->m00, m01 = modelView->m01, m10 = modelView->m10, m11 = modelView->m11;
float a = clip0x * m00;
float b = clip1x * m10;
float c = clip0y * m11;
float d = clip0y * m01;
float e = clip1x * m00;
float f = clip1y * m01;
float g = clip0x * m10;
float h = clip1y * m11;
// If x1 < x2,
if ((clip0x < clip1x) ^ (m00 < 0)) {
// If x2 < x3,
if ((clip0y < clip1y) ^ (m01 < 0)) {
// (x1, y2) -> (x3, y4)
clip.x = a + d;
clip.y = b + c;
clip.width = e + f;
clip.height = g + h;
} else {
// (x4, y1) -> (x2, y3)
clip.x = a + f;
clip.y = g + c;
clip.width = e + d;
clip.height = b + h;
}
} else {
// If x2 < x3,
if ((clip0y < clip1y) ^ (m01 < 0)) {
// (x2, y3) -> (x4, y1)
clip.x = e + d;
clip.y = b + h;
clip.width = a + f;
clip.height = g + c;
} else {
// (x3, y4) -> (x1, y2)
clip.x = e + f;
clip.y = g + h;
clip.width = a + d;
clip.height = b + c;
}
}
clip.width -= clip.x;
clip.height -= clip.y;
clip.x += modelView->m02;
clip.y += modelView->m12;
#endif
// Clip with screen bounds
if (clip.x < 0) {
clip.width += clip.x;
if (clip.width < 0) {
clip.width = 0;
}
clip.x = 0;
}
if (clip.y < 0) {
clip.height += clip.y;
if (clip.height < 0) {
clip.height = 0;
}
clip.y = 0;
}
// If entirely clipped,
if (clip.width <= 0 || clip.height <= 0) {
clip.x = clip.y = clip.width = clip.height = 0;
} else {
// Lookup parent bounds
int i = ctx->mvp - 1;
rect_2d ctx_clip;
ctx_clip.x = ctx->clipStack[i].x;
ctx_clip.y = ctx->clipStack[i].y;
ctx_clip.width = ctx->clipStack[i].width;
ctx_clip.height = ctx->clipStack[i].height;
// If context is on screen,
if (ctx->on_screen) {
// Flip to frame buffer sense
ctx_clip.y = -ctx_clip.y + ctx->canvas->framebuffer_height + ctx->canvas->framebuffer_offset_bottom - ctx_clip.height;
}
// If parent is clipping,
if (ctx_clip.width > -1) {
// Calculate (x1, y1) for new and old clip regions
float clip1x = clip.x + clip.width, clip1y = clip.y + clip.height;
float ctx1x = ctx_clip.x + ctx_clip.width, ctx1y = ctx_clip.y + ctx_clip.height;
// If new clip is entirely outside parent,
if (clip.x >= ctx1x || clip1x <= ctx_clip.x ||
clip.y >= ctx1y || clip1y <= ctx_clip.y) {
// Empty clip region
clip.x = clip.y = clip.width = clip.height = 0;
} else {
// Trim new clip with parent
clip.x = ctx_clip.x > clip.x ? ctx_clip.x : clip.x;
clip.y = ctx_clip.y > clip.y ? ctx_clip.y : clip.y;
clip.width = (ctx1x < clip1x ? ctx1x : clip1x) - clip.x;
clip.height = (ctx1y < clip1y ? ctx1y : clip1y) - clip.y;
}
}
// scissor is with respect to lower-left corner
// activeFrameBufferHeight is the height of the off-screen buffer
// activeFrameBufferOffsetBottom -- the viewport actually goes past the bottom of the texture
// to the nearest power of two, so when we convert to y-coordinates from the lower-left viewport
// corner, we need to add the offsetBottom to get to the bottom of the viewable texture
if (ctx->on_screen && clip.height > 0) {
// Flip from frame buffer sense
clip.y = ctx->canvas->framebuffer_height - (clip.height + clip.y) + ctx->canvas->framebuffer_offset_bottom;
}
}
rect_2d bounds = {
clip.x, clip.y,
clip.width, clip.height
};
if (rect_2d_equals(GET_CLIPPING_BOUNDS(ctx), &bounds)) {
return;
}
*GET_CLIPPING_BOUNDS(ctx) = bounds;
enable_scissor(ctx);
}
