如何绘制位图

Question

>我有在ASM文件中绘制像素的功能。现在我有了所有位图的像素。但是我该怎么画呢？我尝试绘制每个像素的像素 - 但 BMP 文件有 120 000 像素和分辨率请求 160 000。如何绘制位图？（它是24位位图，但我想绘制所有图像）什么是填充物 - Vesa 颜色与此相似吗？谢谢。

编辑：

好的 - 我的 BMP 没有填充字节 - 因此我删除了 dword 对齐方式，它可以工作......如何确定 BMP 何时具有剑对齐？

Answer 1

如何确定 BMP 何时具有剑对齐？

BMP 文件 （DIB） 中的扫描线应始终与 DWORD 对齐，除非图像使用 RLE 压缩（例如，请参阅位图标头类型文档的最后一段）。

可以将每个扫描线的 DWORD 数计算为：

dwords = (int)(((biBitCount * biWidth) + 31) / 32);

（注意：如果是biBitCount == 15，您应该改用 16）。

Answer 2

好的 -

这段代码运行良好 - 只缺少 16 位 BMP - 它正在处理中......

DrawImage:
    cmp word [ID], "BM"
    je DrawBMP
    ret
DrawBMP:
    cmp word [Depth], 24
    je DrawBMP24
    cmp word [Depth], 32
    je DrawBMP32
    ret
DrawBMP24:
    pushad
    mov [.X], eax
    mov [.Y], ebx
    mov [.x], eax
    mov [.y], ebx
    xor edx, edx
    mov [.align], edx
    mov ebx, 4
    mov eax, [Width]
    div ebx
    cmp edx, 0
    je .skip
    mov dword [.align], 1
    xor edx, edx
    mov eax, [Width]
    inc eax
    div ebx
    cmp edx, 0
    je .skip
    mov dword [.align], 2
    xor edx, edx
    mov eax, [Width]
    add eax, 2
    div ebx
    cmp edx, 0
    je .skip
    mov dword [.align], 3
.skip:
    mov esi, BMP
    add esi, [Offset]
    mov [.pointer], esi
    mov ebx, [Height]
    add [.y], ebx
.drawLine:
    mov esi, [.pointer]
    mov al, [esi]
    mov [.color], al
    mov al, [esi + 1]
    mov [.color + 1], al
    mov al, [esi + 2]
    mov [.color + 2], al
    add dword [.pointer], 3
    mov esi, .params
    call DrawPixel
    inc dword [.x]
    mov ebx, [Width]
    add ebx, [.X]
    cmp [.x], ebx
    jne .drawLine
    mov ebx, [.X]
    mov [.x], ebx
    dec dword [.y]
    mov ebx, [.pointer]
    add ebx, [.align]
    mov [.pointer], ebx
    mov ebx, [.Y]
    cmp [.y], ebx
    je .done
    jmp short .drawLine
.done:
    mov dword [.y], 0
    popad
    ret
.X dd 0
.Y dd 0
.align dd 0
.pointer dd 0
.params:
    .color dd 0
    .x dd 0
    .y dd 0
DrawBMP32:
    pushad
    mov [.X], eax
    mov [.Y], ebx
    mov [.x], eax
    mov [.y], ebx
    mov esi, BMP
    add esi, [Offset]
    mov [.pointer], esi
    mov ebx, [Height]
    add [.y], ebx
.drawLine:
    mov esi, [.pointer]
    mov eax, [esi]
    mov [.color], eax
    add dword [.pointer], 4
    mov esi, .params
    call DrawPixel
    inc dword [.x]
    mov ebx, [Width]
    add ebx, [.X]
    cmp [.x], ebx
    jne .drawLine
    mov ebx, [.X]
    mov [.x], ebx
    dec dword [.y]
    mov ebx, [.Y]
    cmp [.y], ebx
    je .done
    jmp short .drawLine
.done:
    mov dword [.y], 0
    popad
    ret
.X dd 0
.Y dd 0
.pointer dd 0
.params:
    .color dd 0
    .x dd 0
    .y dd 0

VESA （VBR） 在这里：

bits 16
org 0x7C00
Boot:
    mov dl, 0x80            ; 80 - FF => HardDisk
    mov si, .imageStruct
    mov cx, 14
.loadPart:
    mov ah, 0x42            ; Extended Read Sectors From Drive
    int 0x13
    add dword [.imageStruct + 6], 2144
    add word [.imageStruct + 8], 67
loop .loadPart
    mov ah, 0x42
    mov si, .kernelStruct
    int 0x13
    jnc InitializeVESA
    mov si, .error
    mov ah, 0xE
    mov cx, 29
.writeChar:
    lodsb
    int 0x10
    loop .writeChar
    mov ah, 0
    int 0x16                ; Wait for keystroke
    mov ax, 0
    int 0x19                ; Reboot the system
.imageStruct:
    dw 16
    dw 67
    dd BMP              ; Offset : Segment
    dq 26
.kernelStruct:
    dw 16               ; byte of structure length + empty byte
    dw sectorsForLoad       ; sectors for load count
    dd Kernel               ; out address
    dq 1                    ; start sector
.error db "Fatal Error! Press any key..."
InitializeVESA:
    in al, 0x92
    or al, 2
    out 0x92, al
    mov bx, 0x4118
    mov ax, 0x4F01
    mov di, ModeInfo
    mov cx, bx
    int 0x10
    mov ax, 0x4F02
    int 0x10
    cli
    lgdt [.GDTR]
    mov eax, cr0
    or al, 1
    mov cr0, eax
; CR0: PG|----RESERVED----|NE|ET|TS|EM|MP|PE
; PE Bit 0. The Protected Environment flag. This flag puts the system into protected mode when set.
; MP Bit 1. The Monitor Coprocessor flag. This flag controls the operation of the "WAIT" instruction.
; EM Bit 2. The Emulate flag. When this flag is set, coprocessor instructions will generate an exception.
; TS Bit 3. The Task Switched flag. This flag is set automatically when the processor switches to a new task.
; ET Bit 4. The Extension Type flag. ET (also called "R") tells us which type of coprocessor is installed. If ET = 0, an 80287 is installed. if ET = 1, an 80387 is installed.
; NE Bit 5. New exceptions. If this flag is clear, FPU exceptions arrive as interrupts. If set, as exceptions.
; PG Bit 31. The Paging flag. When this flag is set, memory paging is enabled. We will talk more about that in a second.
    mov ax, 0x8
    mov ds, ax
    mov es, ax
    mov ss, ax
    jmp 0x10:Kernel
.GDT dq 0, 0xCF92000000FFFF, 0xCF98000000FFFF
; Selector 0x00 cannot be used | 0x10 will be our code | 0x08 will be our data
.GDTR:
    dw 0x1F
    dd .GDT
times 510-($-$$) db 0
dw 0xAA55
%include "source/kernel/SMA.asm"
%include "source/kernel/features/Drawing.asm"
%include "source/kernel/features/Console.asm"
%include "source/kernel/features/Keyboard.asm"
%include "source/kernel/features/KeyMap.inc"
%include "source/kernel/features/Int.asm"
%include "source/kernel/features/String.asm"
times 512 - (($-$$) % 512) db 0
sectorsForLoad equ ($-$$-512) / 512
section .bss
ModeInfo:
    ModeAttributes resw 1
    WinAAttributes resb 1
    WinBAttributes resb 1
    WinGranularity resw 1
    WinSize resw 1
    WinASegment resw 1
    WinBSegment resw 1
    WinFuncPtr resd 1
    BytesPerScanLine resw 1
    ScreenWidth resw 1
    ScreenHeight resw 1
    XCharSize resb 1
    YCharSize resb 1
    NumberOfPlanes resb 1
    BitsPerPixel resb 1
    NumberOfBanks resb 1
    MemoryModel resb 1
    BankSize resb 1
    NumberOfImagePages resb 1
    ReservedPage resb 1
    RedMaskSize resb 1
    RedMaskPos resb 1
    GreenMaskSize resb 1
    GreenMaskPos resb 1
    BlueMaskSize resb 1
    BlueMaskPos resb 1
    ReservedMaskSize resb 1
    ReservedMaskPos resb 1
    DirectColorModeInfo resb 1
    ; VBE 2.0 extensions
    PhysBasePtr resd 1
    OffScreenMemOffset resd 1
    OffScreenMemSize resw 1
resb 206 ; Odsazení od ModeInfo
BMP:
    ID resw 1
    FileSize resd 1
    Reserved1 resb 1
    Reserved2 resb 1
    Reserved3 resb 1
    Reserved4 resb 1
    Offset resd 1
    HeaderLength resd 1
    Width resd 1
    Height resd 1
    NumOfPlanes resw 1
    Depth resw 1
    Compression resd 1
    BytesCount resd 1
    Hresolution resd 1
    Xresolution resd 1
    NumOfUsedColors resd 1
    NumOfImportantColors resd 1