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component:gpu [2020/05/18 03:49] payonel vram docs |
component:gpu [2020/05/18 11:44] payonel |
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| A GPU card has internal memory that you can allocate into pages. You can specify a custom page size (width and height each must be greater than zero). The total memory of a GPU is reduced by the width*height of an allocation. Each tier of gpu has more total memory than the last. Each page buffer acts like an offscreen [[component:screen|Screen]] with its own width, height, and color. The max color depth of a gpu buffer is based on the gpu tier. Rebooting a machine releases all bufffers. | A GPU card has internal memory that you can allocate into pages. You can specify a custom page size (width and height each must be greater than zero). The total memory of a GPU is reduced by the width*height of an allocation. Each tier of gpu has more total memory than the last. Each page buffer acts like an offscreen [[component:screen|Screen]] with its own width, height, and color. The max color depth of a gpu buffer is based on the gpu tier. Rebooting a machine releases all bufffers. | ||
| - | Each page buffer has its own index; the gpu finds the next available index. Index zero (0) has a special meaning, it is reserved for the scren. Whether a gpu is bound to a screen or not, you can allocate pages, set them active, and read/write to them. Attaching and detaching a screen, even binding to a new screen, does not release the gpu pages. When a computer shuts off or reboots, the pages are released. Each GPU has its own video memory and pages. | + | Each page buffer has its own index; the gpu finds the next available index. Index zero (0) has a special meaning, it is reserved for the screen. Whether a gpu is bound to a screen or not, you can allocate pages, set them active, and read/write to them. Attaching and detaching a screen, even binding to a new screen, does not release the gpu pages. When a computer shuts off or reboots, the pages are released. Each GPU has its own video memory and pages. |
| - | - `getBuffer(): number` | + | Budget and Energy Costs |
| + | ----------- | ||
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| + | Updates to vram (set, copy, fill, etc) are nearly free. They have no energy cost and no additional budget cost. Every direct component invoke (and these gpu methods are direct) has a tiny system minimum budget cost, but the gpu itself in these vram updates adds no additional cost. When bitblt'ing the vram to the screen there is some cost, similar to how updates to the screen normally incur a cost. A dirty (modified) vram back buffer has a one time budget cost that increases with the size of the source buffer. Subsequent bitblts from a clean back buffer to the screen have extremely low costs. | ||
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| + | - `getActiveBuffer(): number` | ||
| Returns the index of the currently selected buffer. 0 is reserved for the screen, and may return 0 even when there is no screen | Returns the index of the currently selected buffer. 0 is reserved for the screen, and may return 0 even when there is no screen | ||
| - | - `setBuffer(index: number): number` | + | - `setActiveBuffer(index: number): number` |
| Sets the active buffer to `index`. 0 is reserved for the screen and can be set even when there is no screen. Returns nil for an invalid index (0 is valid even with no screen) | Sets the active buffer to `index`. 0 is reserved for the screen and can be set even when there is no screen. Returns nil for an invalid index (0 is valid even with no screen) | ||
| - `buffers(): table` | - `buffers(): table` | ||