79 lines
1.9 KiB
C
79 lines
1.9 KiB
C
#include "screen.h"
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#include "types.h"
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#include <clib/exec_protos.h>
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#include <exec/memory.h>
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/**
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* Includes double buffer space
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*/
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#define TOTAL_SCREEN_SETUP_SIZE(s) ((s->width / 8) * s->height * s->bitplanes * 2)
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/**
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* Stores internal allocation details in screenSetup.
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* Sets current
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*/
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void allocateDoubleBufferedScreenMemory(
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struct ScreenDefinition *screenDefinition,
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struct ActiveScreenBufferDetails *activeScreenBufferDetails,
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uint16_t width,
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uint16_t height,
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uint8_t bitplanes
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) {
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unsigned char *memory;
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screenDefinition->width = width;
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screenDefinition->height = height;
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screenDefinition->bitplanes = bitplanes;
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memory = (unsigned char *)AllocMem(
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TOTAL_SCREEN_SETUP_SIZE(screenDefinition),
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MEMF_CLEAR | MEMF_CHIP
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);
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screenDefinition->memoryStart = memory;
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screenDefinition->byteWidth = width / 8;
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// memory is not interleaved
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screenDefinition->nextBitplaneAdvance = screenDefinition->byteWidth * height;
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screenDefinition->nextBufferAdvance = screenDefinition->nextBitplaneAdvance * bitplanes;
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setActiveScreenBuffer(screenDefinition, activeScreenBufferDetails, 0);
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}
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void teardownScreen(
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struct ScreenDefinition *screenDefinition
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) {
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FreeMem(
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screenDefinition->memoryStart,
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TOTAL_SCREEN_SETUP_SIZE(screenDefinition)
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);
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}
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void setActiveScreenBuffer(
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struct ScreenDefinition *screenDefinition,
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struct ActiveScreenBufferDetails *currentScreen,
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short int buffer
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) {
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int plane;
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currentScreen->currentBuffer = buffer;
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for (plane = 0; plane < screenDefinition->bitplanes; ++plane) {
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currentScreen->planes[plane] = screenDefinition->memoryStart +
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buffer * screenDefinition->nextBufferAdvance +
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plane * screenDefinition->nextBitplaneAdvance;
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}
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}
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void swapCurrentScreenBuffer(
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struct ScreenDefinition *screenDefinition,
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struct ActiveScreenBufferDetails *currentScreen
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) {
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setActiveScreenBuffer(
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screenDefinition,
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currentScreen,
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1 - currentScreen->currentBuffer
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);
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}
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